First-trimester uterine artery Doppler pulsatility index for prediction of preeclampsia in twin pregnancies: a prospective cohort study / 中华围产医学杂志

ABSTRACT

Objective:To investigate the value of first-trimester uterine artery Doppler pulsatility index (PI) in the prediction of preeclampsia (PE) in twin pregnancies.Methods:From April 2014 to October 2016, women with twin pregnancies undergoing Down's screening at 11 +0-13 +6 gestational weeks in Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine were recruited in this prospective cohort study. Bilateral uterine artery PI values were measured by Doppler ultrasound at the first trimester. Pregnancy outcomes and the incidence of PE were followed up. The participants were classified into four groups according to their pregnancy outcomes: early-onset PE (<34 weeks), late-onset PE (≥34 weeks), gestational hypertension and normal groups. Differences in the multiples of median of uterine artery PI (PI MoM) and rates of abnormal PI MoM (≥ P90) were compared among the four groups using the Kruskal-Wallis test, Chi-square test or Fisher exact test. The performance of uterine artery PI in the prediction of PE was evaluated using receiver operating characteristic (ROC) curve. Results:A total of 1 223 twin pregnancies were recruited and 185 of them were excluded for not meeting the eligibility criteria. The 1 038 cases enrolled successfully were 231 monochorionic diamniotic (MCDA) and 807 dichorionic diamniotic (DCDA) twin pregnancies. The incidences of early-onset PE, late-onset PE and gestational hypertension were 3.47% (36/1 038), 7.03% (73/1 038) and 2.79% (29/1 038), respectively. No significant difference was observed in PI MoM [ M( P25~ P75), 1.06 (0.80-1.32), 1.05 (0.75-1.30), 0.99 (0.73-1.23), 1.03 (0.80-1.27); χ2=0.396, P=0.941] or the rates of abnormal PI MoM [8.33% (3/36), 6.85% (5/73), 13.79% (4/29), 10.11% (91/900); Fisher's exact test, P=0.703] among the four groups. Furthermore, there was no significant difference in PI MoM between normal MCDA and DCDA twin pregnancies [1.04 (0.81-1.29) vs 1.03 (0.79-1.27), χ2=0.095, P=0.758]. The area under the ROC curve showed that first-trimester uterine artery PI had limited value in the prediction of early-onset PE (0.514, 95% CI 0.413-0.615), late-onset PE (0.499, 95% CI 0.428-0.570) and gestational hypertension (0.530, 95% CI0.418-0.643) in twin pregnancies. Conclusion:First-trimester uterine artery PI has limited value in predicting early- or late-onset PE in twin pregnancies.