To determine whether (1) isolated fetal abdominal circumference < 5% (AC5) in absence of growth restriction (estimated fetal weight < 10% [EFW10]) or (2) borderline fetal growth 10 to 19% (EFW10-19) predicts subsequent fetal and/or neonatal growth restriction.Study Design
The authors performed a retrospective cohort study (January 2008 to December 2011) of women with singleton pregnancies between 26 and 36 weeks who had ≥ 1 growth ultrasound. Univariable and multivariable analyses were performed to determine the association between isolated AC5 or EFW10-19 with both subsequent sonographic diagnosis of EFW10 and neonatal diagnosis of small for gestational age (SGA). Test characteristics were calculated.Results
Out of the 10,642 pregnancies, prevalence of isolated AC5, EFW10-19, EFW10, and SGA were as follows: AC5, 5.31%; EFW10-19, 13.30%; EFW10, 7.95%; and SGA, 17.63%. While screening for SGA using EFW10 alone would miss 68.34% of SGA neonates, using isolated AC5 would identify an additional 16.15% of SGA neonates with a 3.7% false positive rate. Using EFW10-19 would identify an additional 40.20% of SGA neonates with a 9.0% false positive rate.Conclusion
Fetuses with isolated AC5 or EFW10-19 are at an increased risk of growth restriction. Using isolated AC5 or composite EFW10-19 would identify SGA neonates that are missed using conventional sonographic definitions of growth restriction alone.