First-trimester uterine artery Doppler indices in term and preterm pre-eclampsia

Objectives To assess the relationship between first-trimester uterine artery Doppler measurements and the development of term and preterm pre-eclampsia. Methods This prospective study of uterine artery Doppler findings at 11-14 weeks in 3058 singleton pregnancies included 57 and 33 cases of term and preterm pre-eclampsia, respectively. Results The first-trimester uterine artery resistance index (RI) was significantly higher in women who subsequently developed preterm pre-eclampsia (mean RI, 0.79) than in those with a normal outcome (mean RI, 0.70; P = 0.0001) or those who developed pre-eclampsia at term (mean RI, 0.72; P = 0.002). There were no significant differences in first-trimester mean uterine artery RI (P = 0.136) or prevalence of bilateral notches (P = 0.459) between women who bad a normal pregnancy outcome and those who developed pre-eclampsia at term. The receiver-operating characteristics curves for the prediction of term and preterm pre-eclampsia by uterine artery Doppler imaging demonstrated a significant association with development of preterm pre-eclampsia (P = 0.0001; area under the curve (AUC), 0.76; 95% CI, 0.66-0.86) but not term pre-eclampsia (P = 0,25; AUC, 0.54; 95% CI, 0.46-0.63). Conclusions The uterine artery Doppler data in this study suggest that preterm pre-eclampsia is strongly associated with defective invasion of the spiral arteries, in contrast to the findings in term pre-eclampsia which may be a consequence of placental deterioration at term. Our study findings support, but do not prove, a rigid separation between the etiology of early- and late-onset pre-eclampsia. Although there is a strong relationship between first-trimester uterine artery Doppler indices and the subsequent development of preterm pre-eclampsia, our data do not support its routine introduction into clinical practice. Copyright (C) 2008 ISUOG. Published by John Wiley & Sons, Ltd.