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.