Objective To develop models for prediction of pre-eclampsia (PE) based on maternal factors and biophysical and biochemical markers at 11-13 weeks' gestation.Methods Screening study of singleton pregnancies at 11-13 weeks including 752 (2.2%) that subsequently developed PE and 32 850 that were unaffected by PE. Models were developed for the prediction of early PE, requiring delivery before 34 weeks, intermediate PE with delivery at 34-37 weeks and late PE delivering after 37 weeks. The data used for the models were firstly, maternal characteristics and history, uterine artery pulsatility index, mean arterial pressure and serum pregnancy-associated plasma protein-A obtained from the screening study and secondly, maternal serum or plasma concentration of placental growth factor, placental protein-13, inhibin-A, activin-A, soluble endoglin, pentraxin-3 and P-selectin obtained from case-control studies.Results In screening for PE by maternal factors only at a fixed false positive rate of 5%, the estimated detection rates were 33.0% for early PE, 27.8% for intermediate PE and 24.5% for late PE. The respective detection rates in screening by a combination of maternal factors, biophysical and biochemical markers were 91.0, 79.4 and 60.9%. ConclusionsEffective prediction of PE can be achieved at 11-13 weeks' gestation.

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.