First trimester uterine artery Doppler in women with previous pre-eclampsia.

OBJECTIVE: To assess the role of first trimester uterine artery Doppler in pregnancies previously complicated by pre-eclampsia. DESIGN AND SETTING: Case-control study in two tertiary referral hospitals. SAMPLE: A total of 56 singleton pregnancies in women with a previous pregnancy complicated by pre-eclampsia (Group 1). For each case, two parous controls (Group 2) and two nulliparous controls (Group 3) with normal pregnancy outcome were matched. METHODS: Doppler examination of the uterine arteries at 11-14 weeks' gestation. MAIN OUTCOME MEASURES: Mean uterine artery resistance index (UtARI) and notching. Pregnancy outcome. RESULTS: UtARI did not vary significantly between the three groups (0.73, 0.70 and 0.71, respectively). Women in Group 1 had a significantly higher prevalence of uterine artery notching than those in Group 2 (73 vs 57%, p=0.04). In Group 1, the UtARI and prevalence of notching was not significantly increased when pregnancies were subsequently complicated by pre-eclampsia (p=0.60 and 0.61, respectively). However, in 12 pregnancies requiring delivery before 37 weeks due to pre-eclampsia, fetal growth restriction, abruption or intrauterine fetal death, the UtARI was significantly higher than in the 44 pregnancies with normal outcome (p=0.04). A combination of UtARI and notching showed sensitivities up to 75% and negative predictive values up to 88% for adverse outcome before 37 weeks. CONCLUSIONS: In pregnancies following a previous gestation complicated by pre-eclampsia, first trimester uterine artery Doppler findings are similar to those observed in nulliparous women. In these high-risk women, a combination of UtARI and notching can predict the risk of adverse outcome before 37 weeks.