Intrapartum fetal head circumference and estimated fetal weight as predictors of operative delivery.

OBJECTIVE: To assess intrapartum sonographic measurements of fetal head circumference (HC) and estimated fetal weight (EFW) to predict operative delivery. METHODS: In a prospective study, 200 spontaneously parturient primiparous women aged 20-30 years were enrolled at a teaching hospital in Cairo, Egypt, between October 2, 2015, and January 28, 2016. HC and EFW were measured by transabdominal ultrasonography. After delivery, the association between type of delivery and ultrasonography findings was assessed. RESULTS: Intrapartum HC and EFW were significantly higher among women with operative delivery (n=76) than among those with normal vaginal delivery (n=124; P<0.001 for both). Intrapartum HC of 36.8 cm or more was associated with an increased risk of operative delivery (relative risk [RR] 2.87, 95% CI 1.87-4.41), as was EFW of 3920 g or more (RR 3.69, 95% CI 2.13-6.40). The area under the receiver operating characteristic curve was 0.807 and 0.748 for HC and EFW, respectively (P<0.001 for both). At 36.8-cm cutoff, HC had 44.7% sensitivity, 91.9% specificity, 77.3% positive predictive value (PPV), and 73.1% negative predictive value (NPV). At 3920-g cutoff, EFW had 68.4% sensitivity, 82.3% specificity, 70.3% PPV, and 81.0% NPV. Intrapartum HC and EFW were directly correlated with second-stage duration (P=0.005 and 0.002, respectively). CONCLUSION: Intrapartum HC and EFW seem to be good predictors of operative delivery.