Clinical study of the association between preeclampsia and chorionicity of twin pregnancies

Objective To identify the association between preeclampsia （PE） and chorionicity of the twin pregnancies and analyze the clinical characteristics. Methods In this retrospective cohort study, 413 women with twin pregnancies were recruited and divided into the monochorionic （MC） and dichorionic （DC） twins groups. The incidence of PE, clinical characteristics and perinatal outcomes were statistically compared between two groups. Results Among 413 cases, 62 women developed PE, including 22 cases in the MC twins group and 40 in the DC twins group. The incidence of PE in the MC twins group was 26.2%, significantly higher compared with 12.2% in the DC twins group （P < 0.001）. In the MC pregnancies with PE, the gestational age upon the onset of PE and gestational week at delivery were significantly earlier and the 24-h urinary protein excretion was remarkably higher than those in the DC counterparts with PE （all P < 0.05）. Additionally, the birth weight was significantly lower, whereas the neonatal asphyxia rate and stillbirth rate in the MC twins group were considerably higher than those in the DC pregnancies （all P < 0.05）. Conclusions MC pregnancies are more likely to develop PE than DC counterparts. In the MC pregnancies, the gestational age upon the onset of PE is earlier and clinical prognosis of perinatal infants is worse than those of DC twins.