First‐trimester screening for early and late small‐for‐gestational‐age neonates using maternal serum biochemistry, blood pressure and uterine artery Doppler

OBJECTIVE To assess the effectiveness of first‐trimester screening for early and late small‐for‐gestational‐age (SGA) neonates using maternal serum biochemistry, blood pressure and uterine artery Doppler . Methods This was a prospective study of 4970 women with a singleton pregnancy who underwent routine first‐trimester screening between 2009 and 2011. A logistic regression‐based predictive model for SGA , defined as birth weight < 10 th percentile, divided into early‐ or late‐onset based on gestational age at delivery before or after 34 weeks' gestation, was constructed. The model included maternal baseline characteristics: serum levels of pregnancy‐associated plasma protein‐A and free β‐human chorionic gonadotropin at 8–12 weeks and blood pressure and uterine artery Doppler at 11 + 0 to 13 + 6 weeks . Results The prevalence of early and late SGA was 0.6% and 7.9%, respectively. Association with pre‐eclampsia was 67% and 8%, respectively. At a false‐positive rate of 15%, the detection rate for early SGA was 73%; however it differed substantially for cases with and without pre‐eclampsia (90% vs 40%). For late SGA , at false‐positive rates of 15 and 50%, detection rates were 32% and 70%, respectively, and did not substantially differ between cases with and without pre‐eclampsia . Conclusions First‐trimester screening predicts early SGA mainly because of its strong association with pre‐eclampsia. Although prediction of late SGA was poorer, at a high false‐positive rate it might be considered as part of a first‐trimester strategy to select women requiring ultrasound assessment in the third trimester. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd .