Customized fetal weight limits for antenatal detection of fetal growth restriction

Objective To define cut-offs limits for individually adjustable fetal weight standards for the detection of intrauterine growth restriction. Design Retrospective study: with the outcome measures small-for-gestational age (SGA) birth weight, operative delivery for fetal distress, umbilical artery pH < 7.15, and admission to the neonatal intensive care unit. Subjects and Methods;Two hundred and fifteen women considered to be at increased risk of uteroplacental insufficiency were recruited to a study of serial ultrasound scans. Fetal weights were derived using standards formula arm, retrospectively, weight percentiles were calculated after individual adjustment for maternal height, weight in early pregnancy: ethnic group, Parity and fetal sex. Introduction One or more antenatal scans indicative of fetal weight below the 10th customized percentile were predictive for a SGA neonate at birth (P < 0.001), operative delivery for fetal distress (P < 0.01) and admission to neonatal intensive care (P < 0.01) but not for a low umbilical artery PH (P = 0.6). Receiver-operator curves,es showed the optimal customized fetal weight percentile limit for predicting all SGA neonate to be the 18th percentile (sensitivity 83%, specificity 79%, Positive predictive value 63% and negitive predictive value 92%). For the prediction of operative delivery for fetal distress and admission to neonatal intensive cave, the optional customised cut-off value was the 8th Percentile. Conclusions Thc assessment of fetal weight using ultra-sound and an individually-adjusted standard is predictive of growth restriction and perinatal events associated with hypoxia or diminished reserve. The optimal cut-off value for Predicting operative delivery for fetal distress of admission to the neonatal intensive care unit suggests that the 10th customized percentile is a good limit for clinical use.