RESUMEN
INTRODUCTION: This study investigated whether fetal growth deceleration in term, appropriate-for-gestational-age (AGA) fetuses is associated with placental insufficiency and nonreassuring fetal heart rate (NRFHR) at birth. METHODS: In this prospective study, 246 low-risk, singleton pregnancies at term with AGA fetuses were recruited. Correlation between decreased growth velocity (decline in estimated fetal weight [EFW] percentile), low EFW (EFWQ1 = latest EFW between 11 and 25% percentiles), umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, and cerebro-placental ratio (CPR) with cesarean and instrumental deliveries due to NRFHR were tested. RESULTS: The median change between fetal weight estimates (percentiles/week) was +0.49% (95% CI: -4 to +5%). Ten percent had decreased EFW percentile >3.5%/week. Fetal growth velocity/week was associated with MCA (r = 0.21, p < 0.001) and CPR (r = 0.24, p < 0.001) and inversely correlated with UA PI (r = -0.28, p < 0.001). NRFHR and cesarean section (CS) rates due to NRFHR were associated with decreased growth velocity, EFWQ1, and low CPR. The combination of abnormal CPR with decreased growth velocity occurred in 12 pregnancies, of which 5 (42%) had urgent CS due to NRFHR. The combination of abnormal CPR with EFWQ1 occurred in 9 pregnancies, of which 4 (44%) had urgent CS due to NRFHR. These combinations increased the likelihood ratio of CS due to NRFHR two-fold (8.41; 2.54-24.5) but did not significantly alter the number needed to treat by elective CS (3.78-4.68). CONCLUSION: Fetal growth velocity, EFW between 10 and 25th percentiles (EFWQ1), and abnormal CPR improves prediction of unplanned CS due to NRFHR among term AGA fetuses. This should be considered when counseling about the delivery method.