Prediction of small-for-gestation neonates from biophysical and biochemical markers at 11-13 weeks.

OBJECTIVE To develop a model for prediction of small-for-gestational age (SGA) neonates in the absence of preeclampsia (PE) based on maternal factors and biophysical and biochemical markers at 11-13 weeks' gestation. METHODS Screening study in 1,536 SGA and 31,314 non-SGA pregnancies based on maternal characteristics, fetal nuchal translucency (NT) thickness, serum pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotrophin (β-hCG). We also measured mean arterial pressure (MAP), uterine artery pulsatility index (PI) and performed case-control studies for measurement of maternal serum concentration of placental growth factor (PLGF), placental protein 13 (PP13) and A Disintegrin And Metalloprotease (ADAM12). Regression analysis was used to develop a model for the prediction of SGA. RESULTS In the SGA group, uterine artery PI and MAP were increased and serum PAPP-A, free β-hCG, PLGF, PP13, and ADAM12 and fetal NT were decreased. At a false positive rate of 10%, the estimated detection rate by a combination of maternal factors and biophysical and biochemical markers at 11-13 weeks was 73% for SGA requiring delivery before 37 weeks and 46% for those delivering at term. CONCLUSIONS Half of pregnancies with SGA neonates in the absence of PE could potentially be identified at 11-13 weeks.