454: Fetal outcomes among growth restricted fetuses by Hadlock versus GROW customized growth chart.

Abstract

Customized growth charts can predict fetuses at high risk of adverse perinatal outcomes associated with fetal growth restriction (FGR), but recent studies do not confirm this. The objective of this study is to assess whether outcomes differ among fetuses identified as FGR (estimated fetal weight (EFW) < 10th percentile) by the standard Hadlock growth chart but as normal (EFW ≥ 10th and ≤ 90th percentile) by the customized gestation-related optimal weight (GROW) chart. This is a retrospective cohort study of prospectively collected data from 70 women identified on prenatal ultrasound as FGR by Hadlock, and for whom relevant covariate data were available. Customized variables including maternal ethnicity, height, weight, parity and fetal sex were used to calculate customized EFW percentiles according to the GROW chart (GROW; version 8.0.3, 2018). Adverse outcome measures were collected including umbilical artery (UA) and middle cerebral artery (MCA) Dopplers, gestational age at delivery, birthweight and Apgar scores. Of 70 FGR fetuses by the Hadlock chart, 60 (86%) were determined to be FGR using the GROW chart and 10 (14%) were determined to have a normal EFW using GROW. The mean gestational age at the time of ultrasound was 30 weeks (210 +/- 22 days). Among the 10 fetuses reclassified by GROW as having a normal EFW, six (60%) had one or more adverse outcomes related to FGR. Doppler abnormalities were present in 2 fetuses (20%), preterm delivery occurred in 1 pregnancy (10%) due to placental abruption, and 4 fetuses (40%) had a birthweight < 10th percentile. None of the reclassified normal EFW fetuses had a 5-minute Apgar score less than 7. Results are summarized in Table 1. Over half of fetuses reclassified from Hadlock-defined growth restriction to a normal EFW using the customized GROW chart experienced adverse outcomes related to growth restriction. Our findings suggest that changing from Hadlock to the GROW chart is not supported. Further analysis should focus on long-term outcome differences between these groups. (Supported by the Perelman Family Foundation)