Prediction of small-for-gestational-age neonates: screening by uterine artery Doppler and mean arterial pressure at 35-37 weeks.

Abstract

To investigate the potential value of uterine artery (UtA) pulsatility index (PI) and mean arterial pressure (MAP) at 35-37 weeks' gestation in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE). This was a screening study in singleton pregnancies at 35-37 weeks, including 245 that delivered SGA neonates with birth weight < 5(th) percentile and 4876 cases unaffected by SGA, PE or gestational hypertension. Multivariable logistic regression analysis was used to determine if UtA-PI and MAP improved the prediction of SGA neonates provided by screening with maternal characteristics and medical history (maternal factors), and estimated fetal weight (EFW) from fetal head circumference, abdominal circumference and femur length. Compared to the normal group, the median multiple of the median (MoM) values of UtA-PI and MAP were significantly higher in the SGA < 5(th) group. Combined screening by maternal factors, EFW Z-score, UtA-PI and MAP at 35-37 weeks predicted, at a 10% false-positive rate, 90%, 86% and 90% of SGA neonates with birth weight < 10(th) , < 5(th) and < 3(rd) percentiles, respectively, delivering < 2 weeks following assessment; the respective values for SGA delivering ≥ 37 weeks were 66%, 74% and 80%. Such performance was not significantly different from screening by maternal factors and EFW Z-score alone. Addition of UtA-PI and MAP to combined testing by maternal factors and fetal biometry at 35-37 weeks does not improve the performance of screening for delivery of SGA neonates.