Detection rate and outcomes in prenatal ultrasound screening for fetal anomalies in low-risk pregnancies from two selected private diagnostic centres, Ibadan, Nigeria

The study, Detection Rate and Outcomes of Prenatal Ultrasound Screening for Fetal Anomalies in Low-Risk Pregnancies at Two Private Diagnostic Centres in Ibadan, Nigeria” aimed to evaluate the detection rate and outcomes of major fetal anomalies among low-risk pregnancies undergoing routine second-trimester ultrasound screening. This retrospective descriptive study reviewed 550 ultrasound records from Nissa Doppler Scan Centre (300) and Pacesetter Diagnostic Centre (250), covering January 2023 to December 2025. Eligible records were those of singleton low-risk pregnancies scanned between 18 and 22 weeks of gestation. Data were analysed using descriptive statistics, 95% confidence intervals and the chi-square test, while diagnostic performance was assessed by comparing prenatal ultrasound findings with available postnatal findings. Major fetal anomalies were detected in 18 of the 550 pregnancies (3.3%; 95% CI: 2.1–5.1). Neural tube defects were the most frequent anomalies (4/18; 22.2%), followed by cardiac, anterior abdominal wall, and renal or genitourinary anomalies (3/18 each; 16.7%). Nine anomalies (50.0%) were detected between 20 and 21 weeks of gestation. Diagnostic assessment yielded 16 true positives, 2 false positives, 1 false negative and 531 true negatives, giving a sensitivity of 94.1% (95% CI: 73.0–99.0), specificity of 99.6%, positive predictive value of 88.9%, and negative predictive value of 99.8%. The proportion of scans with detected anomalies was 3.3% at Nissa Doppler Scan Centre and 3.2% at Pacesetter Diagnostic Centre, with no statistically significant difference (p = 0.93). Of the 18 pregnancies with detected anomalies, 11 (61.1%) resulted in live births, 3 (16.7%) had neonatal morbidity, 2 (11.1%) resulted in stillbirth, and 2 (11.1%) ended in termination of pregnancy. The study concluded that major fetal anomalies were detected in approximately 3.3% of low-risk pregnancies undergoing routine second-trimester ultrasound screening, supporting the recommendation that all pregnant women should be offered routine anomaly screening irrespective of their risk status. However, the sensitivity estimate should be interpreted cautiously because of the small number of confirmed anomalies and potential bias arising from incomplete postnatal verification. Prospective studies with complete postnatal follow-up are therefore recommended.