Uterine artery Doppler ultrasound in second pregnancy with previous elective cesarean section*

OBJECTIVES: To assess the effects of previous cesarean delivery (CD) and placental location on second trimester uterine artery Doppler indices in subsequent pregnancy and to assess the predictive values of abnormal Doppler findings for adverse pregnancy outcomes in women with previous CD. STUDY DESIGN: This prospective cohort study evaluated 400 gravida two pregnant women (200 with previous none medically indicated CD and 200 with previous normal vaginal deliveries (NVD)) who were referred for second trimester fetal anatomic survey. Uterine artery Doppler studies were performed in all participants who were then followed until delivery. RESULTS: Compared with women having prior NVD, women with prior CD had significantly higher rates of abnormal uterine artery pulsatility index (PI) (p < .001), and significantly more adverse pregnancy outcomes (p = .01). Among women with previous CD, all the measured adverse pregnancy outcomes occurred significantly more often in women with abnormal uterine artery Doppler indices (p < .001). CONCLUSIONS: CD seems to be associated with increased risks of impaired placental function and circulation and adverse pregnancy outcomes in the subsequent pregnancy, particularly in women with anteriorly located placenta near the previous uterine scar.