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%.