Pattern and outcome of prenatally diagnosed major congenital anomalies at a Nigerian Tertiary Hospital.

Introduction: The prevalence of major congenital anomalies (CAs) shows wide variations depending on geographical location and may range from <1% to 8% and it causes between 20% and 30% of perinatal deaths. In Nigeria, the prevalence of CAs may be underestimated with the general reliance on mostly livebirths ranging between 0.5% and 2.8% exempting cases of miscarriage and abortions. The purpose of this study was to determine the epidemiologic pattern and outcome of major CAs detected prenatally at the University College Hospital, Ibadan, Nigeria, over a 4-year period.

Methods: This hospital-based descriptive study highlights the prevalence and pattern of prenatally diagnosed fetal anomalies among the pregnant women who presented for routine prenatal ultrasound screening within the study period. Demographic details, associated risk factors, and fetal anomaly type in the fetuses were recorded using a prepared pro forma and were analyzed.

Results: Prenatal ultrasound screening for fetal anomalies was performed on 989 fetuses (including 15 sets of twins and 1 set of triplets) during the study period, out of which 62 (6.3%) had CAs. Of the 62 with CAs, 37 (59.7%) were major and 25 (40.3%) were minor. Majority of the fetuses with major anomalies were found among women aged 30-34 years and most were detected during the routine 18-22 weeks' anomaly scan. The major anomalies were most common in central nervous system. Nine (14.5%) pregnancies were terminated before term and 8 (29.6%) babies had different postnatal surgical interventions. Eleven (17.7%) of the fetuses with anomalies died in the perinatal period.

Conclusion: CAs remain a major contributor to perinatal morbidity and mortality in Nigeria. Since most are idiopathic, early prenatal detection with ultrasound may facilitate improved diagnosis and the reduction of overall perinatal morbidity and mortality in the Nigerian setting.