Systolic, Diastolic and Mean Arterial Pressure at 30-33 Weeks in the Prediction of Preeclampsia

Objective: To investigate the potential value of measuring mean arterial pressure (MAP), systolic (sBP) and diastolic (dBP) blood pressure 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 that were unaffected by PE, gestational hypertension (GH) or delivery of small-for-gestational-age neonates (normal group), 145 that subsequently developed PE [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 determined. The a posteriori risks were calculated by combining the a priori risks with the likelihood ratios for MAP, sBP and dBP, which were calculated from fitted bivariate gaussian distributions. Results: The mean multiple of median MAP, sBP and dBP were significantly higher in the intermediate and late PE groups than in the normal group. In screening by a combination of maternal characteristics and MAP, the estimated detection rates of intermediate and late PE, at a false-positive rate of 10%, were 70.3 and 62.0%, respectively. The respective detection rates for sBP were 62.2 and 59.3% and for dBP were 62.2 and 57.4%. Conclusion: Combined testing by maternal characteristics and blood pressure at 30-33 weeks could effectively identify women at high risk for subsequent development of PE.