Prediction of superimposed preeclampsia using uterine artery Doppler velocimetry in women with chronic hypertension

Objective: To assess the role of uterine artery (UtA) Doppler to predict superimposed preeclampsia in women with chronic hypertension.

Methods: In a cohort of 182 women with chronic hypertension, UtA Doppler studies were performed before 25 weeks (mean 19.7 +/- 2.1 weeks) and repeated later in pregnancy (mean 28.5 +/- 3.7 weeks).

Results: The incidence of preeclampsia was 13% (24/182). Rates of preeclampsia increased with advancing gestation of abnormal UtA Doppler: 7% when UtA Doppler were normal at early exam, 18% when abnormal at early exam, and 28% when abnormal at late exam (Chi-square for trend: P < 0.001). The rate of preeclampsia among 40 women with abnormal early but normal late UtA Doppler was similar to that of women with normal findings at early exam (8 vs 7%; P = 1.00). Logistic regression analysis showed that the ability of UtA Doppler to predict preeclampsia was independent from other variables [Odds Ratio (OR) 7.1, 95% Confidence Interval (CI) 2.6-18.9). Receiver operating characteristic (ROC) curve identified a UtA value of 0.58 as the optimal threshold for the prediction of preeclampsia.

Conclusion: The later in pregnancy the abnormal UtA Doppler findings are observed, the greater the risk of preeclampsia. Normalization of UtA Doppler after 25 weeks reduces the risk of preeclampsia to 8%.