Congenital Malformations (CM) are single or multiple defects of morphogenesis of organs systems identifiable at birth or during the intrauterine life [1]. Congenital malformations pose a major public health problem as they significantly contribute to newborn and infant mortality and morbidity, with a global prevalence of 2-3% [1]. An estimated 7.9 million children are born with major congenital anomalies every year [2]. Majority (>90%) of congenital anomalies occur in low-and- middle income countries (LMIC) [3]. Virtually all organ systems within the body can be affected by congenital malformation. Studies that focus on overt anomalies have identified the musculoskeletal, cardiovascular and gastrointestinal systems as the most commonly affected systems [3,4,5].

The etiology of birth defects is multifactorial and this includes genetic disorders, poor nutrition, ingestion of alcohol, exposure to environmental pollutants such as pesticides, tobacco use, maternal infection and chronic medical disease conditions in the mothers [6-8]. Factors like advanced maternal age, lifestyle, illnesses during pregnancy, lack of antenatal care, family history of congenital malformation, non-use of peri-conceptional folic acid, parental consanguinity, previous miscarriages and unexplained fetal deaths have also been implicated in the etiology of congenital malformations [7,8].

Lack of birth defect registries and poor record keeping is responsible for the dearth of comprehensive data on congenital malformation in LMIC, despite the huge burden [2]. Furthermore, in LMICs factors like home delivery, non-presentation at health facilities, under-reporting, stigmatization, deficient diagnostic capacity and poor awareness are implicated in the gross underestimation of these anomalies in the newborn [9].

This is a retrospective study in which a review of the hospital records of all babies admitted in the Special Care Baby Unit (SCBU) of the Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto over a three-year period (January 2021-Dec 2023) was done. Information was extracted from the record of all the babies admitted with congenital malformation during the 3-year period under review. These include neonatal characteristics, maternal characteristics, nature/type of abnormalities and outcome. Data was checked for completeness and analyzed using IBM SPSS version 23 and 2016 Microsoft Excel. Data e-cleaning and quality checks involved running descriptive statistics of all variables. Frequencies and proportions were computed for categorical variables like gender, age, socioeconomic status, place of delivery. The prevalence of Congenital Malformation (CM) was calculated as the proportion of neonates with CM among the total number of babies admitted during the review period. Proportions were compared using Chi square; p-value <0.05 was considered statistically significant. Ethical approval was obtained from the Health Research and Ethics Committee (HREC) of Usmanu Danfodiyo University Teaching Hospital Sokoto.

Majority of the mothers of babies with congenital malformation were above 30 years of age. Over half (53.1%) of them were from a low socioeconomic class. Mothers whose pregnancies were un-booked predominated (68.1%). A total of 104 (65%) of the mothers used routine antenatal medications during pregnancy (Table 1).

Table 1: Characteristics of mothers whose babies had congenital malformation (n=160).

Of the 2572 babies admitted over the 3-year review period, 164 of them had congenital malformation giving a prevalence rate of 6.4%. Males accounted for 90 (54.9%) while the females were 74 (45.1%). Majority (73.2%) of the newborns were term babies. Over half (56.1%) of the newborns were out-born. The frequency of isolated and multiple congenital malformation was 127(77.4%) and 37(22.6%) respectively. Only 22(13.4%) of the babies had identifiable clinical syndromes. Majority (63.4%) of the babies were discharged while 49 (29.9%) died- Table 2.

Table 2: Characteristics of babies with congenital malformation (n=164).

Table 3 shows the distribution of congenital malformations among the study subjects. A total of 201 congenital defects were identified in164 babies, delivered to 160 mothers. The predominant systems affected were the gastrointestinal, cardiovascular and central nervous systems. The most common congenital malformation seen were omphalocele (11.9%), acyanotic heart disease (11.4%) and neural tube defects (10.9%). One case each (0.5%) of diprosopus and conjoined twins were seen.

Table 3: Distribution of congenital malformation (n=201).

VACTERL; Vertebra, anorectal, cardiac, trachea esophageal, renal, limb anomaly.

Table 4 shows the association between some maternal /neonatal parameters and syndromic congenital malformation. Maternal age > 35 years was significantly associated with syndromic congenital malformation (p=0.003). Non-use of routine ANC medications was also significantly associated with syndromic congenital malformation (p=0.002). Babies that were born outside the study facility had a statistically higher frequency of syndromic congenital malformation compared to the inborn babies (p= 0.032). Factors like maternal infections, maternal exposure to radiation, maternal chronic conditions, baby’s birth weight, baby’s gender were not significantly associated with syndromic congenital malformation (Table 4).

Table 4: Association between maternal/neonatal parameters and syndromic congenital malformation.

X ²= Chi square test, ANC= Antenatal care.

Congenital Malformations (CM) contribute greatly to the burden of neonatal deaths [8]. The prevalence of congenital malformations in this study was 6.4%. This is higher than the prevalence of 2.1% reported in a previous study done in the same study location by Onankpa [10]. This is reflective of an observed increasing trend of congenital malformation globally, despite several preventive measures that have been instituted [11]. This could be due to increased awareness and search for these anomalies and also improved radio-diagnostic facilities. A similar prevalence of 6.1% and 6.3% were reported in some Nigerian studies conducted in Delta state and Oyo state respectively [12,13]. A relatively lower prevalence of 2.8% was reported by Obu in Enugu, Eastern Nigeria [15].

There is a possibility that the figure reported in this present study shows some underestimation of the true burden of congenital anomalies in this part of the country. This present study was conducted in Sokoto state, Northern Nigeria where the frequency of antenatal care visits is relatively low compared to other regions of the country, majority of births occur at home and the health seeking behavior is generally poor [14]. In this study, only 38% of mothers of babies with congenital malformation attended ANC. The predominant systems affected were the gastrointestinal, cardiovascular and central nervous systems, similar to findings in some Nigerian studies [10,12]. The commonest system affected was the gastrointestinal system, a finding corroborated by Onyearugha in Abakaliki, Ebonyi state [16]. However, Ekwochie in Enugu state reported that more than half of the anomalies involved the musculoskeletal system [17]. The commonest anomalies found in this study were omphalocele, acyanotic heart disease and neural tube defects.

Maternal age >35 years was significantly associated with syndromic CM, similar to findings in a study done in Enugu, Nigeria where mothers >35 years had more babies with congenital malformations than those <35 years although not statistically significant in that study, it still reflects the well-known effect of advanced maternal age on the incidence of congenital abnormalities [17,18]. Non-use of routine ANC medications including folate was significantly associated with syndromic CM. This is not surprising considering the fact that the CNS was one of the predominant systems affected, of which neural tube defects were the commonest, a disorder which is largely prevented by the periconceptional use of folate. Babies delivered outside the facility where the study was conducted; either at home or referred from other facilities had a significantly higher frequency of syndromic CM. There is a possibility that some of these babies referred from other facilities or babies delivered at home were delivered to mothers who neither attended ANC nor used their routine ANC medication. A similar finding was reported by Ajao in Ogbomoso, Oyo State Nigeria where a statistically higher proportion of babies referred from other facilities had CM [13].

Congenital malformation is a major indication for admission in Sokoto, North west Nigeria. The predominant systems often affected are the gastrointestinal, cardiovascular and central nervous systems. The commonest congenital malformations seen were omphalocele, acyanotic heart disease and neural tube defects. Advanced maternal age, non-use of ANC medications and out-born babies were factors found to be significantly associated with syndromic CM.

Source of Support

Nil.

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