Diagnostic Performance of Color Doppler Ultrasound for Detecting Nuchal Cord and Associated Immediate Neonatal Outcomes at Term in Uganda: A Prospective Diagnostic‐Accuracy Cohort Study

Abstract

Background and Aims: Evidence on the diagnostic performance of color Doppler ultrasound for detecting nuchal cord and its association with immediate neonatal outcomes remains limited in sub‐Saharan Africa. We evaluated ultrasound detection of nuchal cord and compared immediate neonatal outcomes according to nuchal‐cord status. Methods: This prospective study included 246 women with singleton pregnancies at ≥ 37 weeks who were enrolled in early labor at Mbarara Regional Referral Hospital, Uganda, from February to July 2021. Two‐dimensional and color Doppler ultrasound was performed at enrollment, and direct examination of the umbilical cord at delivery was the reference standard. Diagnostic‐performance measures and unadjusted risk ratios (RRs) were reported with 95% confidence intervals (CIs). Results: Nuchal cord was confirmed at delivery in 88/246 participants in the sampled cohort. Ultrasound identified 76/88 participants with and 152/158 without a nuchal cord. Sensitivity was 86.4% (95% CI: 77.4–92.8), specificity 96.2% (95% CI: 91.9–98.6), positive predictive value 92.7% (95% CI: 84.8–97.3) and negative predictive value 92.7% (95% CI: 87.6–96.2). Overall accuracy was 92.7% (228/246), and the area under the receiver operating characteristic curve was 0.913. The composite immediate adverse neonatal outcome occurred in 18/88 neonates with a nuchal cord and 8/158 without one (20.5% vs. 5.1%; RR: 4.04, 95% CI: 1.83–8.91). Conclusion: Color Doppler ultrasound demonstrated good diagnostic performance for detecting nuchal cord at term. Nuchal cord was associated with higher unadjusted risks of immediate adverse neonatal outcomes, although residual confounding cannot be excluded. Sonographic detection may inform delivery‐room preparedness but should not, in isolation, determine the mode of delivery.