757: Utility of third trimester biometric measurements for predicting SGA in cases of fetal gastroschisis

Abstract

OBJECTIVE: Fetal gastroschisis is associated with SGA in up to 25{%} of cases. Our objective was to determine the predictive utility of third trimester biometric measurements for detecting SGA at delivery. STUDY DESIGN: A retrospective review of fetal gastroschisis cases from two institutions (Loma Linda University and Stanford University) was conducted. For the current study, cases with a third trimester ultrasound exam within 2 weeks of delivery were included. Both institutions use a Hadlock formula for the estimation of fetal weight (EFW) including BPD, HC, AC and FL. Maternal demographic data and individual ultrasound parameters were compared between those with and without SGA at delivery (defined as birth weight less than 10{%} for gestational age). Distribution of normality was evaluated by the Shapiro-Wilk test. Outcomes were evaluated using chi-squared test and Mann-Whitney U-test as appropriate. Logistic regression analysis was used to estimate the probability of SGA using individual parameters and the overall EFW. RESULTS: Of 178 gastroschisis cases, 70 underwent an ultrasound exam within 2 weeks of delivery. Of those 16 pregnancies (22.9{%}) were complicated by SGA. There was no difference in mean maternal age (20.8 vs. 21.6, p=0.314), the gestational age of the ultrasound exam (35.0 vs. 35.3, p=0.690), days between the last ultrasound exam and delivery (6.8 vs. 6.7, p=0.972), or the gestational age of delivery (36.6 vs. 36.5, p=0.883) between those with and without SGA. Women with SGA neonates had a lower pre-pregnancy BMI (21.2 vs. 30.6, p=0.013). There were also statistically significant differences between the total EFW, the BPD, HC, the AC, and FL between those with and without SGA. However, neither the total EFW or individual biometric measurements were found to be predictive of SGA. CONCLUSION: Women with SGA neonates at birth were more likely to have lower BMI prior to pregnancy. However, neither the overall EFW or individual biometric parameters were predictive of SGA at delivery in cases of fetal gastroschisis.