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10.1371/journal.pone.0309298
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Birth Defects
Anorectal Malformations (ARM) and associated maternal factors among children at Tikur Anbessa Specialized Hospital and St. Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia: An unmatched case-control study
Risk factors associated with Anorectal Malformation
Solomon Samrawit Conceptualization Data curation Formal analysis Funding acquisition Investigation Methodology Project administration Resources Software Supervision Validation Visualization Writing – original draft Writing – review & editing 1
Temesgen Fisseha Formal analysis Investigation Methodology Resources Supervision Visualization 2
https://orcid.org/0009-0008-7270-2278
Tibebu Solomon Formal analysis Investigation Methodology Resources Software Supervision Validation Visualization Writing – original draft Writing – review & editing 3 *
Abebe Hana Formal analysis Investigation Methodology Resources Supervision Validation 4
Seyoum Girma Formal analysis Investigation Methodology Supervision Validation Visualization Writing – original draft Writing – review & editing 3
1 Department of Anatomy, School of Medicine, College of Health Sciences and Medicine, Dilla University, Dilla, Ethiopia
2 Department of Surgery, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
3 Department of Anatomy, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
4 Department of Surgery, School of Medicine, St. Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia
Adane Nigat Fentahun Editor
Debre Markos University, ETHIOPIA
Competing Interests: The authors have declared that no competing interests exist.

* E-mail: solomon.tibebu@aau.edu.et
20 9 2024
2024
19 9 e030929823 4 2024
9 8 2024
© 2024 Solomon et al
2024
Solomon et al
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Introduction

Anorectal malformations (ARMs) are birth defects that affect the rectum, anus, and surrounding structures. While genetic and environmental factors may contribute to the risk of developing ARMs, the exact causes are largely unknown. Notably, there is a lack of research investigating predisposing factors for ARMs within the Ethiopian population, despite the burden of this condition in the country.

Objective

The research study aimed at to examine the maternal risk factors linked to the occurrence of anorectal abnormalities in children receiving treatment at designated public hospitals located in Addis Ababa, Ethiopia.

Methods

An unmatched case-control study was conducted at selected hospitals on mothers and their children between August 2022 and January 2023. The sample consisted of pediatric patients admitted to pediatric surgical units. Cases were diagnosed with ARMs, while controls had no congenital anomalies. Data was collected from the mothers of both cases and controls. The data was validated and then exported to SPSS version 26 for analysis. The analysis employed descriptive statistics and binary logistic regression. In a multivariable model, an adjusted odds ratio (AOR) together with a 95% confidence interval and p-value < 0.05 was used to determine significance.

Result

This study included 68 ARM cases and 136 controls. Multivariable analysis found that a family history of birth defects (AOR = 6.15, 95% CI: 1.24–30.58), maternal alcohol use (AOR = 4.71, 95% CI: 1.71–12.00), first-trimester medication use (AOR = 4.86, 95% CI: 1.29–18.32), advanced maternal age (AOR = 4.22, 95% CI: 1.21–14.69), and unplanned pregnancy (AOR = 3.701, 95% CI: 1.551–8.828) were significant risk factors for ARM.

Conclusion

The study found that key risk factors for ARM include family history of birth defects, maternal alcohol use, first-trimester medication use, advanced maternal age, and unplanned pregnancy. These findings underscore the importance of tailored prevention strategies and screening programs to address the genetic, maternal lifestyle, and maternal health factors that contribute to this congenital disorder.

The author(s) received no specific funding for this work. Data AvailabilityWe've made our minimal anonymized data set publicly available on the Open Science Framework (OSF), a recommended platform for sharing research data. You can find the data set at the following URL: [https://osf.io/nrqkx/].
Data Availability

We've made our minimal anonymized data set publicly available on the Open Science Framework (OSF), a recommended platform for sharing research data. You can find the data set at the following URL: [https://osf.io/nrqkx/].
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pmcIntroduction

Anorectal malformation (ARM) is a congenital anomaly that encompasses a wide spectrum of defects involving the anus and rectum, along with the genitourinary system in both sexes. These defects range from minor skin-level issues, such as rectoperineal or anoperineal fistulas, to more complicated defects with associated anomalies [1–4]. The birth prevalence of ARM ranges from 1 in 1500 to 1 in 5000 live births worldwide, with geographical and seasonal variations [4]. Its birth prevalence is 3.59 per 10,000 in Germany and 3.09 per 10,000 in Italy [1, 5]. In South Africa, the prevalence ranges from 1.79 to 3.06 per 10,000, with a male predominance [2].

During normal human embryology, the terminal part of the hindgut forms a structure called the cloaca. Around the seventh week of development, the cloaca splits by the urorectal septum, creating the ventral opening of the urogenital sinus and the anal opening of the hindgut. Most anorectal anomalies result from incomplete separation of the cloaca into urogenital and anorectal portions by the urogenital septum [6]. Lesions of ARM are classified as low or high depending on whether the rectum ends superior or inferior to the pubo-rectalis muscle. The low anomalies of the anorectal region include Anal Agenesis, with or without a Fistula, Anal Stenosis, membranous Atresia of Anus, Anorectal Agenesis, with or without a Fistula. The high anomalies include recto-vesical fistulas, rectovaginal fistulas and recto-bladder neck fistula [3, 6].

According to the new krickenbeck classification system anorectal malformation is classified as major clinical group and rare variation. The major clinical group is further classified as perineal fistula, anal stenosis, recto-urethral fistula, cloacal malformation, recto vesical fistula. The rare variants are sub-classified as rectal stenosis, rectovaginal fistula, H-type fistula and pouch colon [7]. The most frequent ARM subtype in male is recto-urethral fistula and vestibular fistula in female. About 48%-78% ARM are associated with other anomalies [8, 9].

The etiology of anorectal malformations (ARMs) are the subject of ongoing research and debate. The tendency to develop ARMs is believed to result from the combined influence of various genetic and environmental factors, rather than being due to a single causal element. While genetic factors have been associated with ARMs, the precise genetic mechanisms are not fully understood. In rare syndromic types of ARMs, such as Townes–Brocks syndrome, Down syndrome, and Currarino syndrome, the cause can be explained solely by genetic factors, such as mutations in specific genes and chromosomal structural abnormalities [3]. However, for the majority of ARMs, the underlying genetic basis is more complex. Animal experiments have shown that problems in the SHH (sonic hedgehog signaling molecule) and TCF4 (transcription factor 4) genes, which are important in the development of the digestive tract during human embryology, can result in ARMs [10].

However in non-syndromic types, in addition to genetic factors, environmental risk factors have also been identified. These include maternal smoking [11], maternal obesity [12], maternal diabetes [12], maternal overweight [13], previous miscarriage [14], and maternal chronic respiratory disease [15]. Understanding the full range of predisposing factors, both genetic and environmental, will be crucial for developing comprehensive strategies for the prevention and management of anorectal malformations.

ARMs represent a significant burden for pediatric surgery, both in developed and developing countries. Literature from Africa in particular has distinguished ARMs as the leading congenital anomaly and the most common cause of neonatal gastrointestinal obstruction among congenital pediatric surgery cases [16–18]. Research conducted in Nigeria and Uganda found that ARMs account for a substantial proportion of congenital anomaly cases, at 21.2% and 19% respectively. Additionally, ARMs were the leading cause of intestinal obstruction, responsible for 57–67% of such cases in these countries [2, 16, 17, 19]. These findings underscore the disproportionate impact of ARMs on pediatric surgical caseloads, especially in resource-constrained settings. Addressing this public health challenge will require concerted efforts to improve early diagnosis, access to specialized surgical care, and long-term management strategies for affected children and their families.

While there is limited research on the birth prevalence and incidence of ARMs in Ethiopia, hospital based studies have highlighted the substantial burden of this condition on the country’s pediatric surgery units. A study conducted at Tikur Anbessa Specialized Hospital (TASH) from 2010 to 2014 found that gastrointestinal tract (GIT) problems accounted for 43.3% of all neonatal surgical cases, with ARMs representing 19% of these GIT-related congenital anomalies and 24% of all neonatal surgical cases [20].

Furthermore, a separate five-year retrospective study at TASH identified ARMs as the first of the top ten congenital anomalies (8.9%) requiring surgical intervention, and the second most common cause of pediatric admissions after foreign body swallowing [21]. In addition, ARMs were also shown to be the most common cause of intestinal obstruction in the early new-born period, accounting for 57% of cases, followed by intestinal atresia (13%) and Hirsschsprung’s disease (12%) in a study conducted at the TASH neonatal care unit [22]. Furthermore, a study at Jimma Medical Centre between 2017 and 2019 found that ARMs, primarily imperforate anus, were the third most common congenital anomaly (9%), preceded only by spinal bifida (14.6%) and clubfoot (12.56%) [23].

These findings underscore the significant impact of ARMs on pediatric surgical caseloads in Ethiopia. The high burden ARMs in this population highlights the pressing need for increased research efforts to better understand the underlying causes, risk factors, long-term outcomes, and prevention strategies of these congenital anomalies.

Despite the substantial burden of ARMs, there is a paucity of literature quantifying the determinants or risk factors associated with the development of this condition in Ethiopia or across the African continent. Understanding the specific maternal risk factors could aid in preparing prenatal caregivers for early recognition and timely interventions. This knowledge could allow healthcare providers to counsel women on modifiable risk factors, optimize antenatal care, implement targeted interventions during pregnancy, and inform strategies for prevention. To address this gap, the present study aims to identify potential risk factors associated with the development of ARM.

Method

Study area and period

This study was conducted at Tikur Anbessa Specialized Hospital (TASH) and St Paul’s Hospital Millennium Medical College (SPHMMC) pediatric Surgical units from August 2022-January 2023 G.C. TASH is Ethiopia’s largest territory hospital, by far. It provides comprehensive medical services to both the local population and referred patients from other areas. Moreover, TASH stands out as one of the few specialized hospitals in the country that specifically caters to pediatric surgical needs. Located in the northwestern part of Addis Ababa, SPHMMC is a tertiary hospital in the city. The Department of Surgery at SPHMMC is organized into three units, with the pediatric surgery unit being one of them.

Study design

A hospital-based unmatched case-control study was conducted, where the participants included pediatric patients admitted to the pediatric surgical units with a diagnosis of ARM as cases, and pediatric patients without any congenital anomaly who sought treatment of other illnesses during the study period as controls.

Source population

All children with anorectal malformation and their mothers who received care at Tikur Anbessa Specialized Hospital and St Paul’s Hospital Millennium Medical College in Addis Ababa, Ethiopia during the study period of August 2022 to January 2023.

Study population

This includes Children with ARM (cases) and children without the condition (controls), along with their mothers, who were selected from the source population at the same two hospitals during the time period between August 2022 and January 2023).

Study unit

All mothers of both control and case groups.

Diagnosis of ARM

Patients were diagnosed with ARM through a two-step process. Pediatric surgeons first conducted a clinical examination to identify the characteristic features. If the clinical findings were unclear, a perineal ultrasound was performed to confirm the diagnosis. Only patients with a definitive ARM diagnosis confirmed by this combined clinical and imaging approach were included in the study.

Inclusion/exclusion criteria

Children diagnosed with anorectal malformations (ARM) with the above diagnostic approach and admitted with their biological mothers were included as the case group. However, the study excluded any children admitted with a caregiver other than their biological mother, for both the case and control groups. Furthermore, the control group excluded any children diagnosed with other congenital anomalies.

Sample size determination

Sample size was calculated using the Epi Info 7 statistical software package. The study used a two-sided significance level of 95%, a power of 80%, a control-to-case ratio of 2:1, and an estimated exposure status of 7.2% for cases and 0.2% for controls [13]. Since the data collection involved retrospective chart reviews and interviews with mothers of children born with ARM, rather than long-term participant follow-up, a 5% non-response rate was determined to be adequate for the study. With these considerations, the sample size calculation yielded 68 cases and 136 controls, resulting in a total of 204 participants.

Sampling procedure

The calculated sample size was allocated proportionally between the two centers, taking into account the total number of ARM patients at TASH and SPHMMC from January 2019 to January 2022 [S1 File]. A total of 287 new patients were treated for ARM at the two centers during the specified period. Since ARM is a rare condition, all the identified cases were taken until the required sample size reached. Two controls were chosen on the same day for every ARM case using a systematic random sampling method.

Data collection

The data collection tools were adapted from different previous peer-reviewed studies. The first version of the questionnaire was prepared in English (S2 File) and then was translated into Amharic. It was then re-translated to the English language by another person to check its semantic equivalence. Data was collected from mothers of cases and controls using pretested and structured face-to-face, interviewer-administered questionnaires. This was also supplemented with visual observation of the medical records of the child and the mother.

Study variables

Dependent variable

Anorectal malformation (yes or no).

Independent variables include

The independent variables in our study include: socio demographic characteristics, parity, prior obstetric complication (abortion, still birth or early neonatal death), history of antenatal care (ANC) follow up, pregnancy Intention (planed vs unplanned), family history of birth defect in the first and second degree relatives, history of maternal illnesses during or prior to pregnancy, maternal exposure to medications, history of folic acid intake during the pregnancy, body mass index (BMI) during pregnancy, alcohol ingestion, maternal exposure to pesticides (insecticides, herbicides, or fungicides) during first trimester of pregnancy.

Data quality assurance

In order to ensure the quality of data, the principal investigator recruited and trained data collectors. Two nurses with a BSc degree with previous experience were assigned to conducted face to face interview with mothers. One BSc degree in public health was assigned to supervise data collectors in the process of data collections. The training included an overview of the research objectives, data collection techniques and the utilization of data collection tools especially on how to interview as well as fill the questionnaires and check lists properly. To ensure the reliability of the questionnaire, a pre-test was conducted on 5% (3 cases and 7 controls) of the total sample size prior to the actual data collection. Throughout the data collection period, the principal investigator conducted daily reviews and checks of the collected data for any omissions as well as assessing completeness and consistency.

Statistical analysis

Data were entered using Epi Info version 7 and cleaned and analyzed in SPSS version 26. Following descriptive analysis, tabular presentations including frequency distributions and cross-tabulations were used to present the results. Categorical variables were analyzed using the chi-square (χ²) test. Fisher’s exact test was used when the assumptions for the chi-square test for association were not met. We performed a bivariable logistic regression analysis for each maternal risk factor individually to assess its association with the outcome variable, ARM. The crude odds ratio (COR) and the corresponding 95% confidence interval (CI) for each maternal risk factor were determined and the statistical significance of the association was evaluated using the p-value.

All the maternal risk factors identified as potentially significant in the bivariable analysis (P<0.25) were analyzed using multivariable logistic regression model to estimate the independent effects of each maternal risk factor on odds of ARM, while controlling for potential confounding factors. Adjusted odds ratios (AORs) and the corresponding 95% CIs for each maternal risk factor were determined in the multivariable model. Maternal risk with a p-value less than 0.05 was considered statistically significant factors associated with the occurrence of ARM.

Multiple model fit measures were employed to make a more well-rounded evaluation of the model’s goodness of fit. Based on the results of the likelihood ratio test, Hosmer-Lemeshow goodness-of-fit test, and the pseudo R-squared measures, the logistic regression model appears to fit our data reasonably well. Variance inflation factor (VIF) was used to measure multicollinearity. The VIF values in our study were below 10, indicating the absence of concerning multicollinearity.

Operational definitions

Anorectal malformations:- The absence of an anus or an abnormal anus, with or without a fistula, and they were classified according to the Krickenbeck criteria [7].

Alcohol Consumption: Self-reported intake of alcoholic beverages, including beer, wine, and distilled spirits (e.g., liquor, spirits, hard liquor) with frequency of 1 or more drink per day.

Passive smoking: Regular exposure to tobacco smoke from the smoking of others at home or work place for an extended period (several hours per day or multiple days per week) during pregnancy.

Active smoking: Smoking cigarettes during pregnancy, regardless of the number of cigarettes smoked per day.

Exposure to Pesticide: Any documented or self-reported use, handling, or environmental contact with chemical pesticides including insecticides, herbicides, fungicides, and rodenticides, in a home or occupational setting. Exposure could occur through various routes, including living close to places where pesticides are frequently used and applying, mixing, or spraying pesticides directly.

Ethical clearance

Ethical approval for the study was obtained from the Department of Research Ethics Review Committee (DRERC) at the Department of Anatomy, School of Medicine, and Addis Ababa University, with reference number DRERC/06/22 dated June 2022. Additionally, approval was granted by the institutional review board (IRB) of St. Paul’s Hospital Millennium Medical College, with reference number PM 23/291, dated December 2022. The study procedure and its objectives were disclosed to all participants. Participants were informed that their participation was voluntary and could be withdrawn at any time, and that non-participation would not affect the services they received from the hospital.

Written and signed consent was obtained from all study participants before administering the questionnaires and conducting face-to-face interviews. Participants were not required to write their names on the questionnaires to maintain confidentiality, and no identifying information was recorded. The data were used solely for the purposes of the study to ensure confidentiality.

Results

Socio-demographic characteristics of mothers

In this study, a total of 204 (68 cases and 136 controls) mothers were identified and interviewed at the pediatrics surgical units, achieving a response rate of 100%. About 87.5% of mothers for controls and more than half for cases 76.5% were in the age group of 20–34 years. The patients were from different parts of the country, 60.3% for controls and 38.2% for cases came from Addis Ababa, while the remaining from other regions of the country. Regarding educational status of the mothers 35.3% for cases and 39.7% for controls were high school graduates. About 67.6% of mothers for cases and 94.9% of mothers for controls were urban residents (Table 1).

10.1371/journal.pone.0309298.t001 Table 1 Socio-demographic characteristics of mothers included in the study conducted at specific hospitals located in Addis Ababa, Ethiopia, during the year 2022.

	Case (%)	Control (%)	
Characteristics	(N = 68),N(%)	(N = 136),N(%)	
Mothers age			
 15–20	0	10 (7.3)	
 20–34	52 (76.5)	119 (87.5)	
 > 34a	16 (23.5)	7 (5.2)	
Mother’s Education			
 Illiterate	22 (32.4)	3 (2.2)	
 Read and write	3 (4.4)	14 (10.3)	
 Elementary education	10 (14.7)	36 (26.5)	
 High school education	24 (35.3)	54 (39.7)	
 Higher education	9 (13.2)	29 (21.3)	
Mother’s Occupation			
 Housewife	39 (57.3)	95 (69.8)	
 Student	1 (1.5)	2 (1.6)	
 Government employee	13 (19.1(	15 (11)	
 Private employee	10 (14.7)	22 (16)	
 Farmer	5 (7.4)	2 (1.6)	
Mother’s region			
 Addis Ababa	26 (38.2)	82 (60.3)	
 Oromia	30 (44.1)	33 (24.3)	
 Amhara	8 (11.8)	11 (8.1)	
 SNNP	3 (4.4)	7 (5.1)	
 Afar	1 (1.5)	0 (0)	
 Somalia	0 (0)	3 (2.2)	
Place of Residence			
 Urban	46 (67.6)	129(94.9)	
 Rural	22 (32.4)	7(5.2)	
Religion			
 Orthodox	37 (54.4)	78 (57.3)	
 Muslim	23 (33.8)	42 (30.9)	
 Protestant	8 (11.8)	16 (11.8)	
a Advanced maternal age

SNNP, South Nations and Nationalities

Reproductive and obstetric history of respondents

In the study, the majority of women were multipara, with 54(79.4%) for cases and 83(61%) for controls. Approximately 44.1% of the pregnancies for the cases were unplanned, compared to 13.2% for the controls. Furthermore, the majority of mothers gave birth at term (37–42 weeks), with 89.7% for cases and 89.7% for controls, while a small percentage gave birth before 37 weeks, with 4.4% for cases and 7.3% for controls.

Around 22.1% of mothers for cases and 16.2% for controls had a history of previous obstetric complications (abortions and still birth). About 13.2% of mothers for cases and 2.9% for controls reported a family history of birth defects. Among all mothers, only a small percentage did not attend antenatal care follow-up, with 3% for controls and 11.8% for cases. About 43% of mothers for the case group and 81.6% for the control group were taking folic acid supplementation during their pregnancy, but only 22% of mothers for cases and 47.1% for controls took folic acid supplementation in the first trimester of pregnancy (Table 2).

10.1371/journal.pone.0309298.t002 Table 2 Reproductive and obstetric characteristics of mothers included in the study, conducted at specific hospitals located in Addis Ababa, Ethiopia, during the year 2022.

Characteristics	Case (%)	Control(%)	
	(N = 68),N(%)	(N = 136),N(%)	
Parity			
 Multiparous	54 (79.4)	83 (61)	
 Primiparous	14(20.6)	53 (39)	
Gestational age at delivery			
 Preterm	3 (4.4)	10(7.3)	
 Term a	61(89.7)	122(89.7)	
 Post term	4(5.9)	4 (3)	
ANC follow up			
 Yes	60 (88.2)	132(97)	
 No	8 (11.8)	4 (3)	
Lack of Folic acid intake during pregnancy			
 yes	53 (77.9)	72(52.9)	
 No	15 (22.1)	64(47.1)	
Past obstetric complication b			
 Yes	15 (22.1)	8 (16.2)	
 No	53 (77.9)	128 (83.8)	
Unplanned pregnancy			
 Yes	30 (44.1)	18 (13.2)	
 No	38 (55.9)	118 (86.8	
Family History of birth defect			
 Yes	9 (13.2)	4 (2.9)	
 No	59 (86.8)	132 (97.1)	
ANC, antenatal care

a 37–42 weeks of gestational age

b abortion, still birth.

Maternal medical, lifestyle and environmental factors

The majority of mothers had a normal body mass index, with 40(68.4%) for cases and 93(59%) for controls. Approximately 25% of mothers were overweight, with 19(28%) for cases and 33(24.3%) for controls. In our study maternal medical illness during pregnancy was seen in 44% of mothers for cases and 16.2% of mothers for controls. Out of this the commonest medical illnesses were Urinary tract infection and anemia. Out of the study participants, medication use in first trimester of pregnancy was noticed in 22% of mothers for cases and 5.9% of mothers for controls. Alcohol consumption during first trimester of pregnancy was reported in about 30.9% of mothers for case and 9.6% for controls. About 5.9% of mothers for cases and 0.7% for controls had history of passive cigarette smoking during their first trimester of pregnancy. In addition, about 17.6% of mothers for cases and 2.9% for controls were exposed to pesticides in the first trimester pregnancy (Table 3).

10.1371/journal.pone.0309298.t003 Table 3 Medical, lifestyle, and environmental exposure characteristics of mothers included in the study, conducted at specific hospitals located in Addis Ababa, Ethiopia, during the year 2022.

Characteristics	Case (%)	Control (%)	
Maternal medical illness			
 Yes	30 (44.1)	22 (16.2)	
 No	38 (55.9)	114 (83.8)	
Types of maternal medical illness			
 DM	1(1.5)	2(1.5)	
 Anemia	7 (10.3)	4(2.9)	
 UTI a	12(17.6)	6(4.4)	
 Epilepsy	1(1,5)	0(0)	
 Other b	9(13.2)	10(7.3)	
Body mass index (Kg/m2)			
 Under weight	5 (7.3)	7(5.1)	
 Normal	40 (59)	93(68.4)	
 Over weight	19 (28)	33(24.3)	
 Obese	4 (5.7)	3 (2.2)	
Medication use in the 1st trimester			
 yes	15(22)	8(5.9)	
 No	53(78)	128(94.1)	
Alcohol consumption			
 Yes	21(30.9)	13(9.6)	
 No	47(69.1)	123(90.4)	
Passive smoking in the 1st trimester			
 Yes	4(5.9)	1(0.7)	
 No	64(94.1)	135(99.3)	
Active smoking			
 Yes	0	2(1.5)	
 No	68 (100)	134	
Exposure to Pesticide in the 1st trimester			
 Yes	12(17.6)	4(2.9)	
 No	56(82.4)	132(97.1)	
a Urinary tract infection

b Hypertension, HIV, HPV, Asthma, DVT, STI, and Febrile illness

Risk factors associated with anorectal malformation

Bivariable Binary logistic regression analyses revealed significant associations between ARM and maternal exposure to various factors during their first trimester of pregnancy. These factors included alcohol consumption, medication use, passive cigarette smoking, maternal medical illness, exposure to pesticides, lack of folic acid supplementation, advanced maternal age (age >35 years), history of obstetric complication, and family history of birth defects. Factors such as maternal education, occupation, parity and maternal obesity were not found to have a statistically significant association with ARM.

The variables that were found to be statistically significant in the bivariable binary logistic regression were passed into the next level of statistical analysis, multivariable logistic regression. After applying both bivariable and multivariable binary logistic regression only five variables had showed an overall significant association with the development of ARM at 5% level of significance. Accordingly, women who consumed alcohol during the first trimester of pregnancy were 4.7 times more likely to give birth to newborns with ARM compared to those who did not drink alcohol (Adjusted Odds Ratio (AOR) = 4.71; 95% Confidence Interval (CI) = 1.71 to 12.00). Similarly, women who had a history of taking medication for various illnesses during the first trimester of pregnancy had a 5-fold increased likelihood of having newborns with ARM (AOR = 4.86; 95% CI = 1.29 to 18.32).

In addition, advanced maternal age during pregnancy, defined as age over 35 years, was also associated with a 4-fold higher odds of having a newborn with ARM compared to younger mothers (AOR = 4.22; 95% CI = 1.21 to 14.69). Unplanned pregnancy was significantly associated with the occurrence of ARM, with an AOR of 3.70 and a 95% CI of 1.55 to 8.83. Furthermore, the study identified a statistically significant association between family history of birth defects and ARM, where mothers with a family history in first and second-degree relatives had 6 times higher odds of having a child with ARM compared to those without such a family history (AOR = 6.15; 95% CI = 1.24 to30.58)(Table 4).

10.1371/journal.pone.0309298.t004 Table 4 Bivariate and multivariate binary logistic regression analysis examining risk factors for ARM among mothers visiting at specific hospitals in Addis Ababa, Ethiopia, during 2022.

Characteristics	Case (%)	Control (%)	COD,95% CI	AOD 95% CI	P-value	
ANC follow up						
 Yes	60 (88.2)	132 (97.1)	0.227(0.07,0.78)	0.742(0.12, 4.59)	0.744	
 No	8 (11.8)	4 (2.9)	1	1		
Advanced maternal age a						
 Yes	16 (23.5)	7 (5.1)	5.670(2.21,14.58)	4.22 (1.21, 14.69)	0.024*	
 No	52 (76.5)	129 (94.9)	1	1		
Maternal illness						
 Yes	30 (44.1)	22 (16.2)	4.091 (2.11,7.92)	2.27 (0.89, 5.72)	0.085	
 No	38 (55.9)	114 (83.8)	1	1		
Medication use						
 Yes	15 (22)	8 (5.9)	4.528(1.81, 11.36)	4.86 (1.29, 18.32)	0.02*	
 No	53 (78)	128 (94.1)	1	1		
Family history of birth defect						
 Yes	9 (13.2)	4 (2.9)	5.034 (1.49, 17.00)	6.15 (1.24, 30.58)	0.026*	
 No	59 (86.8)	132 (97.1)	1	1		
Passive Smoking						
 Yes	4 (5.9)	1 (0.7)	8.437 (0.92,77.02)	6.85 (0.32, 43.39)	0.292	
 No	64 (94.1)	135 (99.3)	1	1		
Exposure to Pesticide						
 Yes	12 (17.6)	4 (2.9)	9.500 (2.58, 34.97)	2.53 (0.49, 12.89)	0.265	
 No	56 (82.4)	132 (97.1)	1	1		
Lack Folic acid intake during the 1st trimester						
 Yes	53 (77.9)	72 (52.9)	3.141 (1.62, 6.12)	2.31 (0.98, 5.42)	0.055	
 No	15 (22.1)	64 (47.1)	1	1		
Unplanned pregnancy						
 Yes	30 (44.1)	18 (13.2)	5.175(2.60, 10.31)	3.70 (1.55, 8.83)	0.003*	
 No	38 (55.9)	118 (86.8	1	1		
Past obstetric complication						
 Yes	15 (22.1)	8 (16.2)	4.528(1.81, 11.32)	1.44 (.44, 4.72)	0.545	
 No	53 (77.9)	128 (83.8)	1	1		
Alcohol consumption						
 Yes	21 (30.9)	13 (9.6)	4.617 (2.12,10.12)	4.71 (1.71,12.00)	0.003*	
 No	47 (69.1)	123 (90.4)	1	1		
COR, Crude odds ratio; AOR, Adjusted odds ratio; CI, Confidence interval

*indicates statistical significance.

a age >34years.

Discussion

Existing literature suggests that ARM is a multifactorial condition, involving both genetic and environmental factors that play a role in its pathogenesis. This study investigated the association between a number of the maternal factors and the development of ARMs. In the present study, individuals with a family history of birth defects, maternal alcohol consumption, medication use, advanced maternal age and unplanned pregnancy were found to be significantly associated factors with ARM.

Several environmental factors have been investigated in different studies as risk factors of ARM, but the results have been inconsistent and heterogeneous. In our study, children with a family history of birth defects including ARM in their first and second-degree relatives were more likely to develop ARM than those without a family history. Our results are consistent with research from Germany and the Netherlands that observed an increased risk of ARM in those with a family history of birth abnormalities [11–13].

Our research suggests that maternal alcohol consumption during early pregnancy may increase the risk of ARM, which is consistent with studies conducted in Japan on patients with ARM [24, 25]. This association may be due to the fact that alcohol exposure can disrupt normal embryonic development processes such as cell proliferation, migration, and differentiation by crossing the placental membrane. However, studies conducted in Germany, the Netherlands, and Sweden did not find a significant association between alcohol consumption and the occurrence of ARM [13, 25, 26]. One possible explanation for these contradictory findings is that the effects of alcohol on embryonic development depend on the dose, timing, duration, and pattern of exposure. Furthermore, differences in cultural alcohol consumption patterns across various communities may have contributed to the observed differences as well.

This study found that medication use during the first trimester of pregnancy is another potential risk factor for ARM. This result aligns with other studies, including a meta-analysis on maternal drug use and ARM occurrence. The meta-analysis discovered links between ARM and various drug categories [26]. A research study conducted in Ethiopia on congenital anomalies also reported this association [24]. However, some reports did not find a significant association between medication use during pregnancy and ARM [11, 13]. These conflicting results in the literature may be due to various factors, such as differences in study design, sample size, and the specific medications investigated.

In our literature search, we were unable to find a study that specifically demonstrated a link between ARM and advanced maternal age. However, many research studies have documented a link between advanced maternal age and the occurrence of other congenital anomalies. We found that both advanced maternal age and unplanned pregnancy were associated with a higher risk of developing ARM. The possible mechanism for the association could be the fact that older mothers have a higher risk of genetic mutations and an increased incidence of aneuploidy, which could potentially contribute to the development of ARM [27–29].

The present study found that women with unplanned pregnancies had a higher likelihood of giving birth to children with ARM compared to those with planned pregnancies. A direct association between ARM and unplanned pregnancy had not been reported previously. However, the existing literature has demonstrated increased risks of other congenital anomalies, such as congenital heart diseases [30], and neural tube defects [31], among pregnancies that were unintended.

The potential reasons for the higher risk of anorectal malformation observed in unplanned pregnancies could be multifaceted. Firstly, unplanned pregnancies may be associated with a lower likelihood of receiving timely and comprehensive prenatal care [32]. Secondly, during an unintended pregnancy, women may be more likely to be exposed to various risk factors that can contribute to the development of ARM, such as certain medications, infections, or environmental exposures. These risk factors may be more prevalent or less controlled in the context of an unplanned pregnancy. Lastly, an unintended pregnancy can be a significant source of stress for the mother. Elevated maternal stress levels have been linked to an increased risk of various congenital abnormalities, including ARM, potentially due to the physiological effects of stress on fetal development [33].

Furthermore, the present study found that several factors, including maternal BMI, maternal medical illness during pregnancy, lack of folic acid intake, and passive smoking, did not have a significant association with the occurrence of ARM. This contrasts with other studies conducted in Germany, the Netherlands, Sweden, China, and Japan, where one or a combination of these factors were found to be associated with ARM, resulting in inconsistent findings [11, 13, 34]. The variation in results across different studies may be due to differences in study design, such as variations in the definition and classification of ARM, sample size, recruitment strategies, and data collection and analysis methods.

Additionally, differences in healthcare practices and access to prenatal care may also contribute to the heterogeneity in the results. For instance, limited access to prenatal screening and diagnostic tests in some regions could affect the detection and reporting of ARM cases.

Strengths of the study

Comprehensive investigation of a wide range of potential risk factors for ARMs.

Employment of trained, experienced health professionals for data collection, and evaluation/diagnosis of ARMs by pediatric surgeons, ensuring expertise and accuracy.

Limitations of the study

As this was a hospital-based study, there is a possibility that the researchers may have missed patients who did not seek medical treatment, potentially introducing selection bias.

Since the study was not community-based, it may be difficult to extrapolate the conclusions to the target population at large.

Recall bias may have been introduced, as information about maternal exposure was obtained retrospectively.

ARMs are relatively rare congenital anomalies, and the sample size in an unmatched case-control study may have been limited, reducing the statistical power to detect significant associations.

Conclusion

The study findings indicate that anorectal malformation (ARM) risk is substantially elevated for infants with a family history of birth defects, as well as for those whose mothers consumed alcohol or took medications during the first trimester of pregnancy. Additionally, advanced maternal age and unplanned pregnancy emerged as other significant contributing factors. These results underscore the importance of pre-pregnancy and prenatal care to identify and mitigate key risk factors, in order to help prevent the occurrence of this congenital abnormality. The identified risk factors suggest a need for a multifaceted approach addressing genetic, maternal lifestyle, behavioral, and health-related influences to effectively reduce the burden of ARM. Further population-based research is needed to more comprehensively examine the relationship between maternal risk factors and anorectal malformations.

Supporting information

S1 File Sampling procedure.

(PDF)

S2 File Consent form (English and Amharic version).

(DOCX)

S3 File English version questionnaire.

(PDF)

The researchers would like to express their deepest gratitude to all the staff members of the Department of Pediatric Surgery at Addis Ababa University and St. Paul’s Hospital Millennium Medical College for their invaluable support throughout the study. The researchers’ gratitude also extends to the trained data collectors at each of the participating hospitals in the study area. Their dedicated efforts in data collection were instrumental in the successful completion of this research project.

10.1371/journal.pone.0309298.r001
Decision Letter 0
Adane Nigat Fentahun Academic Editor
© 2024 Fentahun Adane Nigat
2024
Fentahun Adane Nigat
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submission Version0
23 May 2024

PONE-D-24-13124Maternal risk factors associated with Anorectal malformation at selected governmental hospitals in Addis Ababa, Ethiopia, 2023: A case–control studyPLOS ONE

Dear Dr. Tibebu,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

Thank you for providing the manuscript titled "Maternal risk factors associated with Anorectal malformation at selected governmental hospitals in Addis Ababa, Ethiopia, 2023: A case–control study". As an academic editor, I have the following comments and questions:

Introduction:

The introduction provides a good overview of anorectal malformations and the need to assess maternal risk factors. However, it could be strengthened by including more details on the specific knowledge gaps or limitations of previous studies that this study aims to address.

It would be helpful to include the research objectives more clearly, perhaps as a separate paragraph at the end of the introduction.

Methods:

The study design, setting, and sampling approach are clearly described. It would be good to provide more details on how the sample size was calculated, such as the expected effect size, power, and significance level used.

The data collection and analysis methods are well-explained. It would be useful to include information on how anorectal malformations were diagnosed and classified in this study.

The statistical analysis plan is comprehensive, but it would be helpful to explain the rationale for using both bivariate and multivariate analyses.

Results:

The results are presented clearly and the key findings are highlighted. It would be good to include a table summarizing the demographic and clinical characteristics of the study participants.

The interpretation of the results, particularly the adjusted odds ratios, could be strengthened by discussing the plausibility and potential mechanisms underlying the observed associations.

Discussion:

The discussion section provides a good synthesis of the key findings and compares them to existing literature. It would be valuable to discuss the strengths and limitations of the study design and how they may have influenced the results.

The concluding remarks could be expanded to highlight the public health implications of the findings and propose future research directions.

Overall:

The manuscript is generally well-written and organized. Consider improving the flow between sections and ensuring consistent terminology (e.g., "ARM" vs. "anorectal malformation"). Check the formatting and ensure all references are complete and correctly cited. In summary, this is a well-designed and conducted study that contributes to the understanding of maternal risk factors for anorectal malformations in the Ethiopian context. With some revisions to strengthen the introduction, methods, results interpretation, and discussion, this manuscript would be a valuable addition to the literature.

. Be sure to:Indicate which changes you require for acceptance versus which changes you recommend

Address any conflicts between the reviews so that it's clear which advice the authors should follow

Provide specific feedback from your evaluation of the manuscript

==============================

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We look forward to receiving your revised manuscript.

Kind regards,

Fentahun Adane Nigat, PhD

Academic Editor

PLOS ONE

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Additional Editor Comments:

Thank you for providing the manuscript titled "Maternal risk factors associated with Anorectal malformation at selected governmental hospitals in Addis Ababa, Ethiopia, 2023: A case–control study". As an academic editor, I have the following comments and questions:

Introduction:

1. The introduction provides a good overview of anorectal malformations and the need to assess maternal risk factors. However, it could be strengthened by including more details on the specific knowledge gaps or limitations of previous studies that this study aims to address.

2. It would be helpful to include the research objectives more clearly, perhaps as a separate paragraph at the end of the introduction.

Methods:

3. The study design, setting, and sampling approach are clearly described. It would be good to provide more details on how the sample size was calculated, such as the expected effect size, power, and significance level used.

4. The data collection and analysis methods are well-explained. It would be useful to include information on how anorectal malformations were diagnosed and classified in this study.

5. The statistical analysis plan is comprehensive, but it would be helpful to explain the rationale for using both bivariate and multivariate analyses.

Results:

6. The results are presented clearly and the key findings are highlighted. It would be good to include a table summarizing the demographic and clinical characteristics of the study participants.

7. The interpretation of the results, particularly the adjusted odds ratios, could be strengthened by discussing the plausibility and potential mechanisms underlying the observed associations.

Discussion:

8. The discussion section provides a good synthesis of the key findings and compares them to existing literature. It would be valuable to discuss the strengths and limitations of the study design and how they may have influenced the results.

9. The concluding remarks could be expanded to highlight the public health implications of the findings and propose future research directions.

Overall:

The manuscript is generally well-written and organized. Consider improving the flow between sections and ensuring consistent terminology (e.g., "ARM" vs. "anorectal malformation"). Check the formatting and ensure all references are complete and correctly cited. In summary, this is a well-designed and conducted study that contributes to the understanding of maternal risk factors for anorectal malformations in the Ethiopian context. With some revisions to strengthen the introduction, methods, results interpretation, and discussion, this manuscript would be a valuable addition to the literature.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: General: It is a relevant topic. It needs proper editing of language usage and for consistent use of terms, figures and flow of idea and avoid repetitive notes

1. Abstract

Settings: Not proper description of study area in methods section of the manuscript

ODK: It is not mentioned in the body (methods) of the manuscript

2. Methods

a. The methods section needs further reorganization

b. The methods section should clearly show the study area, period, settings, design, sampling technique (controls), variables of interest, data collection procedure, data quality assurance methods and analysis methods and only information included in this section can be reported in the abstract section.

c. Why were other congenital anomalies other than ARM were also excluded? (exclusion criteria should be described well)

d. What does non-ARM related disease mean?

e. Hospital based or population based control selected?

f. Inclusion of children: Is this reflected in the analysis?

g. What is the target population of study? Children with ARM or Mothers?

h. Mention as oral consent in other part of the study?

i. Why was 5% used as non-response mark than the usual 10%?

j. How was data quality control assured?

k. How was variable selection made for inclusion (p-values) in the multivariable analysis

l. How was multicollinearity checked?

m. How was the final model of multivariable regression checked?

3. Results

a. How was the overall response rate?

b. Illness: Did you check separately or in groups for each disease entity for significance? (statistical significance might have been different)

c. What does unspecified medications mean?

d. How was it different with different groups of illness analyzed above? (statistical significance might have been different)

e. Which trimester of pregnancy was of interest in data collection? Was the pre-pregnancy period considered? (mainly for medication, alcohol and smoking)

f. Was maternal smoking status assessed other than passive smoking?

g. Redundant paragraph information

h. Check again, some of the %s do not add up to 100% on tables

i. Check again for chi-square assumption in each cell; some of the cells need regrouping for analysis

4. Discussion

a. Only results addressed in the results section and pertinent factors should be included in the discussion

b. General terms should be avoided like, sampling technique, design etc in the discussion section on result alignment or disparity

c. Conclusion

Re-write focused to the study findings; pertinent to the study results, future suggestions, limitations of the study should be raised here

Reviewer #2: The work you have done is very substantial for evidence based birth defects, particularly in the context of anorectal malformations. However, I believe that certain adjustments are necessary to correct editorial and grammatical issues, as well as specific suggestions in each part.

Reviewer #3: Overall

This manuscript addressed an important topic. Appropriate design was used. The discussions and conclusions provided were based on the findings of the study. However, the manuscript shall address the following concerns. The manuscript lacks page and line numbers. This made it providing comments very difficult. The writing quality of the manuscript should be improved. I recommend language editing. There are several typos and grammar problems. E.g. Typos: “Alcohol conception” and “written concent”. A single sentence was placed as a paragraph in several parts of the manuscript. E.g. “By considering 5% non-responding rate, the calculated sample was 68 cases and 136 controls and a total of 204 sample size (9).” and “The data was entered and analyzed using Statistical Package Social Sciences (SPSS) version 26 software.”

Introduction

The introduction is very brief. Authors would have provided evidence about the magnitude of the problem in the international and local settings. The rational of conducting the study was not well stated.

Methods and materials

Authors shall rewrite the methods section. Authors need to go through all the common subsections of the methods section. The manuscript lacks detailed information on data collection tool and the data collectors. Similarly, it lacks on how the data quality was assured.

The authors shall clearly state at which specific unit/department of the hospitals the cases and controls were recruited.

Variables such as Alcohol consumption, Exposure to Pesticide and Passive smoking need to be operationally defined.

The statistical analysis should have been consistently stated. Authors’ mention of “univariate”, “multivariate”, and “multinomial” are not appropriate for a case control study that used binary logistic regression analysis.

Result

Authors shall rewrite this section. The result was not written in a standard way. Authors report the result in an inconsistent manner. The descriptive and analytic results were reported in a mixed manner. It is better to rewrite the result as the descriptive first, followed by association of ARM with predictor variables. Start the associations first by listing the candidate variables for the multivariable analysis and then interpreting the variables that showed significant associations in the multivariable associations.

While the authors employed odds ratio (OR) as a measure of association, the association result has been interpreted as if it is a relative risk (RR). This mistake is serious and has to be corrected in all of the association interpretations.

While Table 1 includes reproductive and obstetric factors, the table tittle mentions only socio-demographic variables.

Discussion

The strength of this manuscript is its discussion. However, it can still be improved by providing scientific justifications for the associated variables. The last paragraph of the discussion shall contain the strength and limitation of the study.

Conclusion

The first two statements “Several studies were conducted on the risk factors of ARM. However, these studies are inconsistent and heterogeneous.” shall better be removed from the conclusion. Authors shall put recommendations based on their conclusion.

**********

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Reviewer #1: No

Reviewer #2: Yes: Bickes Wube Sume

Reviewer #3: Yes: Mihretu Jegnie

**********

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Attachment Submitted filename: Reviewers notes.docx

Attachment Submitted filename: Reviewers notes on document (1).docx

Attachment Submitted filename: review report.docx

10.1371/journal.pone.0309298.r002
Author response to Decision Letter 0
Submission Version1
16 Jul 2024

AUTHOR’S RESPONSE TO ACADEMIC EDITOR COMMENT

Dear editor

I greatly appreciate your wonderful, inspiring, and motivating comments on our manuscript. We value your insightful and helpful feedback, which we believe will enhance the quality of our work. The following changes have been made in response to your suggestions.

INTRODUCTION

� Include more details on the specific knowledge gaps or limitations of previous studies that this study aims to address.

Answer - Included in more detail as commented. The previous research studies performed at Tikur Anbessa Specialized Hospital (TASH) and Jimma University Hospital had solely focused on investigating and quantifying the overall burden the medical condition in question. However, up until this point, no studies have been conducted to explore or identify the potential underlying determinants or associated factors that may contribute to the development and occurrence of this particular condition.

�Include the research objectives more clearly, perhaps as a separate paragraph at the end of the introduction.

Answer- Comment accepted. Included in more detail as a separate paragraph at the end of the introduction section

METHODS:

o The study design, setting, and sampling approach are clearly described. It would be good to provide more details on how the sample size was calculated, such as the expected effect size, power, and significance level used.

Answer – comment accepted and corrected accordingly

o The data collection and analysis methods are well-explained. It would be useful to include information on how anorectal malformations were diagnosed and classified in this study.

Answer - The materials and methods section of the paper discusses the process used to diagnose anorectal malformations (ARM) in the study participants. However, as the focus of this research project was not on examining the specific patterns or classifications of the different types of ARM, it may not be necessary to provide a detailed discussion of ARM classification schemes within the methods section, as that information may not be directly relevant to the primary goals of the study. Instead, the introduction section of the paper already included a thorough overview of the most up-to-date classification system for anorectal malformations.

o The statistical analysis plan is comprehensive, but it would be helpful to explain the rationale for using both bivariate and multivariate analyses.

Answer – comment accepted and corrected accordingly. The rationale for using bivariable binary logistic regression and multivariable logistic regression was discussed in the revised manuscript in detail.

RESULTS

o The results are presented clearly and the key findings are highlighted. It would be good to include a table summarizing the demographic and clinical characteristics of the study participants.

Answer - Comment accepted. I included one additional table showing the

Pregnancy and obstetric characteristics of the study participants.

o The interpretation of the results, particularly the adjusted odds ratios, could be strengthened by discussing the plausibility and potential mechanisms underlying the observed associations.

Answer - The strength of association between the dependent and independent variables was discussed with reference to the AOR. The discussion section provides a good synthesis of the key findings and compares them to existing literature.

o It would be valuable to discuss the strengths and limitations of the study design and how they may have influenced the results.

Answer - Comment accepted. Limitations related to the study design like recall

Bias and lack of power were included in the revised manuscript.

o The concluding remarks could be expanded to highlight the public health implications of the findings and propose future research directions.

Answer - Included as commented

Overall:

The manuscript is generally well-written and organized. Consider improving the flow between sections and ensuring consistent terminology (e.g., "ARM" vs. "anorectal malformation").

Check the formatting and ensure all references are complete and correctly cited. In summary, this is a well-designed and conducted study that contributes to the understanding of maternal risk factors for anorectal malformations in the Ethiopian context. With some revisions to strengthen the introduction, methods, results interpretation, and discussion, this manuscript would be a valuable addition to the literature.

. Be sure to:

• Indicate which changes you require for acceptance versus which changes you recommend

• Address any conflicts between the reviews so that it's clear which advice the authors should follow

• Provide specific feedback from your evaluation of the manuscript.

Feedback

We thoroughly reviewed and updated the entire manuscript. We carefully considered and incorporated each specific suggestion and comment provided by the manuscript reviewers. We found the feedback from the reviewers to be extremely valuable and beneficial. The reviewer comments significantly improved the overall quality and structure of the final manuscript.

Attachment Submitted filename: REBUTAL LETTER FOR ACCADEMIC EDDITOR.docx

10.1371/journal.pone.0309298.r003
Decision Letter 1
Adane Nigat Fentahun Academic Editor
© 2024 Fentahun Adane Nigat
2024
Fentahun Adane Nigat
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submission Version1
9 Aug 2024

Anorectal malformation and associated maternal factors among Children at Tikur Anbessa Specialized Hospital and St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia: Unmatched case–control study

PONE-D-24-13124R1

Dear Dr. Solomon,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

Fentahun Adane Nigat, MSc., PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

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Reviewer #2: All comments have been addressed

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Reviewer #1: I appreciate the authors for positively entertaining all the comments suggested in the review process. All comments are included or justified reasonably. However, the article may still benefit from thorough editing in language /grammar.

Thank you!

Reviewer #2: I would like to acknowledge the authors for their rigorous work. My comments and suggestions were addressed fully.

Reviewer #3: (No Response)

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Reviewer #1: Yes: Megbar Dessalegn

Reviewer #2: Yes: Bickes Wube Sume

Reviewer #3: Yes: Mihretu Jegnie

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10.1371/journal.pone.0309298.r004
Acceptance letter
Adane Nigat Fentahun Academic Editor
© 2024 Fentahun Adane Nigat
2024
Fentahun Adane Nigat
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
11 Sep 2024

PONE-D-24-13124R1

PLOS ONE

Dear Dr. Tibebu,

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References

1 Cassina M , Fascetti Leon F , Ruol M , Chiarenza SF , Scirè G , Midrio P , et al . Prevalence and survival of patients with anorectal malformations: A population-based study. J Pediatr Surg. 2019;54 (10 ):1998–2003. doi: 10.1016/j.jpedsurg.2019.03.004 30935729
2 Lawal TA . Overview of Anorectal Malformations in Africa. Front Surg. 2019;6 :7. doi: 10.3389/fsurg.2019.00007 30891450
3 Levitt MA , Peña A . Anorectal malformations. Orphanet J Rare Dis. 2007;2 :33. doi: 10.1186/1750-1172-2-33 17651510
4 Kluth D. Embryology of anorectal malformations. Semin Pediatr Surg. 2010;19 (3 ):201–8. doi: 10.1053/j.sempedsurg.2010.03.005 20610193
5 Jenetzky E. Prevalence estimation of anorectal malformations using German diagnosis related groups system. Pediatr Surg Int. 2007;23 (12 ):1161–5. doi: 10.1007/s00383-007-2023-6 17929037
6 Moore Keith L. , T VN Persaud Torchia MG . The Developing Human: Clinically Oriented Embryology. 10th ed: Elsevier Health Sciences; 2015. p. 239–41.
7 Holschneider A , Hutson J , Peña A , Beket E , Chatterjee S , Coran A , et al . Preliminary report on the International Conference for the Development of Standards for the Treatment of Anorectal Malformations. J Pediatr Surg. 2005;40 (10 ):1521–6. doi: 10.1016/j.jpedsurg.2005.08.002 16226976
8 Banu T , Karim A , Adel MG , Lakhoo K , Aziz TT , Das A , et al . Multicenter Study of 342 Anorectal Malformation Patients: Age, Gender, Krickenbeck Subtypes, and Associated Anomalies. Eur J Pediatr Surg. 2020;30 (5 ):447–51. doi: 10.1055/s-0039-1695789 31655491
9 Nah SA , Ong CC , Lakshmi NK , Yap TL , Jacobsen AS , Low Y . Anomalies associated with anorectal malformations according to the Krickenbeck anatomic classification. J Pediatr Surg. 2012;47 (12 ):2273–8. doi: 10.1016/j.jpedsurg.2012.09.017 23217888
10 Carter TC , Kay DM , Browne ML , Liu A , Romitti PA , Kuehn D , et al . Anorectal atresia and variants at predicted regulatory sites in candidate genes. Ann Hum Genet. 2013;77 (1 ):31–46. doi: 10.1111/j.1469-1809.2012.00734.x 23127126
11 Kapapa M , Becker N , Serra A . Risk factors for anorectal and associated malformations in German children: A 10-year analysis. Pediatr Neonatol. 2021;62 (1 ):97–105.33071156
12 Zwink N , Jenetzky E , Brenner H . Parental risk factors and anorectal malformations: systematic review and meta-analysis. Orphanet J Rare Dis. 2011;6 :25. doi: 10.1186/1750-1172-6-25 21586115
13 van Rooij IA , Wijers CH , Rieu PN , Hendriks HS , Brouwers MM , Knoers NV , et al . Maternal and paternal risk factors for anorectal malformations: a Dutch case-control study. Birth Defects Res A Clin Mol Teratol. 2010;88 (3 ):152–8. doi: 10.1002/bdra.20649 20073076
14 van de Putte R , Wijers CH , de Blaauw I , Marcelis CL , Sloots CE , Brooks AS , et al . Previous miscarriages and GLI2 are associated with anorectal malformations in offspring. Hum Reprod. 2017;32 (2 ):299–306. doi: 10.1093/humrep/dew327 28057877
15 van de Putte R , de Blaauw I , Boenink R , Reijers MHE , Broens PMA , Sloots CEJ , et al . Uncontrolled maternal chronic respiratory diseases in pregnancy: A new potential risk factor suggested to be associated with anorectal malformations in offspring. Birth Defects Res. 2019;111 (2 ):62–9. doi: 10.1002/bdr2.1429 30569656
16 Ullrich SJ , Kakembo N , Grabski DF , Cheung M , Kisa P , Nabukenya M , et al . Burden and Outcomes of Neonatal Surgery in Uganda: Results of a Five-Year Prospective Study. J Surg Res. 2020;246 :93–9. doi: 10.1016/j.jss.2019.08.015 31562991
17 Moore SW , Sidler D , Hadley GP . Anorectal malformations in Africa. S Afr J Surg. 2005;43 (4 ):174–5. 16440593
18 Lawal T , Adeleye A , Ayede A , Ogundoyin O , Olulana D , Olusanya A , et al . Congenital paediatric surgical cases in Ibadan: patterns and associated malformations. Afr J Med Med Sci 2017;46 :49–55.
19 Ameh EA , Chirdan LB . Neonatal intestinal obstruction in Zaria, Nigeria. East Afr Med J. 2000;77 (9 ):510–3. doi: 10.4314/eamj.v77i9.46702 12862145
20 Shitaye N , Dejene B . PATTERN AND OUTCOME OF NEONATAL SURGICAL CASES AT TIKUR ANBESSA UNIVERSITY TEACHING HOSPITAL, ADDIS ABABA, ETHIOPIA. Ethiop Med J. 2016;54 (4 ):213–20. 29115120
21 Mohammed M , Amezene T , Tamirat M . Intestinal Obstruction in Early Neonatal Period: A 3-Year Review Of Admitted Cases from a Tertiary Hospital in Ethiopia. Ethiop J Health Sci. 2017;27 (4 ):393–400. doi: 10.4314/ejhs.v27i4.10 29217941
22 Amezene Robelie A. Gossaye , Derbew M . Pediatrics Surgical Admissions and Procedures in Tikur Anbessa Specialized Hospital, Ethiopia: A five-year retrospective study. Ethiopian Medical Journal. 2019; 57 (3 ):235–40.
23 Silesh Mulualem , Lemma Tesfanesh , Fenta Belete , Biyazin T . Prevalence and Trends of Congenital Anomalies Among Neonates at Jimma Medical Center, Jimma, Ethiopia: A Three-Year Retrospective Study. Dove Press journal: Pediatric Health, Medicine and Therapeutics. 2021;12 :61–7.
24 Taye M , Afework M , Fantaye W , Diro E , Worku A . Factors associated with congenital anomalies in Addis Ababa and the Amhara Region, Ethiopia: a case-control study. BMC Pediatr. 2018;18 (1 ):142. doi: 10.1186/s12887-018-1096-9 29699508
25 Yuan P , Okazaki I , Kuroki Y . Anal atresia: effect of smoking and drinking habits during pregnancy. Jpn J Hum Genet. 1995;40 (4 ):327–32. doi: 10.1007/BF01900599 8851766
26 Zwink N , Jenetzky E . Maternal drug use and the risk of anorectal malformations: systematic review and meta-analysis. Orphanet J Rare Dis. 2018;13 (1 ):75. doi: 10.1186/s13023-018-0789-3 29747656
27 Hvide HK , Johnsen J , Salvanes KG . Parental age and birth defects: a sibling study. Eur J Epidemiol. 2021;36 (8 ):849–60. doi: 10.1007/s10654-021-00734-8 33761052
28 Materna-Kiryluk A , Wiśniewska K , Badura-Stronka M , Mejnartowicz J , Wieckowska B , Balcar-Boroń A , et al . Parental age as a risk factor for isolated congenital malformations in a Polish population. Paediatr Perinat Epidemiol. 2009;23 (1 ):29–40. doi: 10.1111/j.1365-3016.2008.00979.x 19228312
29 Gedamu S , Sendo EG , Daba W . Congenital Anomalies and Associated Factors among Newborns in Bishoftu General Hospital, Oromia, Ethiopia: A Retrospective Study. J Environ Public Health. 2021;2021 :2426891. doi: 10.1155/2021/2426891 33859704
30 Liu Z , Wang M , Tang Q , He F , Li N , Deng Y , et al . Unintended pregnancy-related factors and the occurrence of offspring congenital heart disease: a multi-site case-control study in China. Eur J Contracept Reprod Health Care. 2021;26 (3 ):221–6. doi: 10.1080/13625187.2020.1862081 33624567
31 Dolin CD , Deierlein AL , Evans MI . Folic Acid Supplementation to Prevent Recurrent Neural Tube Defects: 4 Milligrams Is Too Much. Fetal Diagn Ther. 2018;44 (3 ):161–5. doi: 10.1159/000491786 30134243
32 Birhanu K , Tesfaye W , Berhane M . Congenital Anomalies in Neonates Admitted to a Tertiary Hospital in Southwest Ethiopia: A Cross Sectional Study. Ethiop J Health Sci. 2021;31 (6 ):1155–62. doi: 10.4314/ejhs.v31i6.10 35392332
33 Carmichael SL , Shaw GM , Yang W , Abrams B , Lammer EJ . Maternal stressful life events and risks of birth defects. Epidemiology. 2007;18 (3 ):356–61. doi: 10.1097/01.ede.0000259986.85239.87 17435445
34 Myers MF , Li S , Correa-Villaseñor A , Li Z , Moore CA , Hong SX , et al . Folic acid supplementation and risk for imperforate anus in China. Am J Epidemiol. 2001;154 (11 ):1051–6. doi: 10.1093/aje/154.11.1051 11724722
