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Objectives

Objective: To investigate the potential value of measuring uterine artery pulsatility index (PI) at 30-33 weeks' gestation in the prediction of preeclampsia (PE) developing at or after 34 weeks. Methods: Screening study in singleton pregnancies at 30-33 weeks' gestation including 4,294 cases that were unaffected by PE, gestational hypertension (GH) or delivery of small for gestational age neonates (normal group), 145 that subsequently developed PE, with 37 cases requiring delivery at 34-37 weeks (intermediate-PE) and 108 delivering at or after 38 weeks (late-PE) and 161 that developed GH. The a priori risks for intermediate- and late-PE from maternal demographic characteristics and medical history were derived by logistic regression analysis. The a posteriori risks were calculated by combining the a priori risks with the likelihood ratios for uterine artery PI, which were calculated from fitted bivariate gaussian distributions. Results: In screening for PE by a combination of maternal characteristics and uterine artery PI, the estimated detection rates of intermediate- and late-PE, at a false-positive rate of 10%, were 70.3 and 54.6%, respectively. Conclusion: Combined testing by maternal characteristics and uterine artery PI at 30-33 weeks could effectively identify women at high risk for subsequent development of PE.

Objective: To investigate the potential value of maternal serum concentrations of free β-human chorionic gonadotrophin (β-hCG), pregnancy-associated plasma protein-A (PAPP-A) and placental growth factor (PlGF) at 30-33 weeks of gestation in the prediction of pre-eclampsia (PE) developing at or after 34 weeks. Methods: Serum free β-hCG, PAPP-A and PlGF were measured at 11-13 and at 30-33 weeks of gestation in a case-control study of 50 cases that developed PE at or after 34 weeks and 250 unaffected controls. The measured concentration of metabolites was converted into multiples of the unaffected median (MoM) and the MoM values in the PE and control groups were compared. Results: At 11-13 weeks, serum PlGF and PAPP-A, but not free β-hCG, were significantly lower in the PE group than in the controls (0.824, 0.748 and 0.857 vs. 1.000 MoM). At 30-33 weeks in the PE group, PlGF was reduced (0.356 MoM), free β-hCG was increased (1.750 MoM), but PAPP-A was not significantly different (0.991 MoM) from control (1.000 MoM). In screening for PE at 30-33 weeks by a combination of maternal characteristics and serum PlGF, the estimated detection rates, at a false-positive rate of 10%, of intermediate PE (requiring delivery at 34-37 weeks) and late PE (with delivery after 37 weeks) were 85.7 and 52.8%, respectively. The performance of screening was not improved by the addition of free β-hCG or the free β-hCG/PlGF ratio. Conclusion: Screening by maternal characteristics and serum PlGF at 30-33 weeks could identify most pregnancies that will subsequently develop PE.