Prevalence of Congenital Anomalies in Low-Risk Pregnancies in Zaria, Nigeria.

Background: Congenital anomalies are a major cause of perinatal morbidity and mortality worldwide. Although prenatal ultrasonography is the primary method for detecting structural fetal anomalies, evidence on their prevalence among low-risk pregnancies in Nigeria remains limited. The objective of this study is to determine the sonographic prevalence of congenital fetal anomalies among low-risk pregnant women attending antenatal clinics in Zaria, Northwestern Nigeria. Methodology: This hospital-based cross-sectional study was conducted between March and September 2024 among 570 low-risk pregnant women attending Ahmadu Bello University Teaching Hospital, Kofar Gaya General Hospital, and the University Health Services (Sick Bay), Zaria. Participants underwent routine second-trimester fetal anomaly scans following standardized ultrasound protocols. Data were analysed using descriptive statistics, and the prevalence of congenital anomalies was calculated with 95% confidence intervals. Results: The mean maternal age was 26.0 ± 5.1 years, while the mean gestational age at ultrasound examination was 21.2 ± 2.2 weeks. Eight fetuses were diagnosed with congenital anomalies, giving an overall prevalence of 1.4% (95% CI: 0.6-2.8%). Central nervous system anomalies were the most common abnormalities, followed by cardiac and urogenital anomalies. Some affected fetuses had anomalies involving more than one organ system. Conclusion: Congenital fetal anomalies occur even among pregnancies considered clinically low risk. These findings support routine second-trimester fetal anomaly screening for all pregnant women to facilitate early diagnosis, appropriate counselling, and timely obstetric management.