Improved prediction of preeclampsia by two-stage screening of uterine arteries using the early diastolic notch and color Doppler imaging.

Abstract

To assess the value of the early diastolic notch and color Doppler imaging of the uterine arteries at 24 weeks' gestation in a two-stage Doppler screening test for preeclampsia. Two thousand fifty-eight unselected women had an initial screening study with continuous-wave Doppler at 18-22 weeks' gestation. Color Doppler imaging was used at 24 weeks' gestation to examine both uterine arteries in 273 women with initial abnormal results (high resistance index or diastolic notch). Three hundred twenty-nine women (16%) had abnormal flow velocity waveforms at the first stage and 104 (5.1%) at the second stage of Doppler screening. The presence of an early diastolic notch in the flow velocity waveform was significantly better than a high resistance index at predicting preeclampsia at both 20 and 24 weeks; the relative risk of developing significant preeclampsia for a woman with a persistent notch at 24 weeks was increased 68-fold. All women delivered before 34 weeks because of severe preeclampsia had abnormal waveforms at both stages of screening. An early diastolic notch in the flow velocity waveform is a better predictor of preeclampsia than are conventional impedance indices. Preeclampsia can be predicted effectively by two-stage Doppler screening.