Clinical features and influencing factors for prematurity in both dichorionic and monochorionic diamniotic twins

Abstract

Objective To investigate the risk factors of preterm birth, as well as the clinical characteristics in dichorionic diamniotic (DCDA) twins and monochorionic diamniotic (MCDA) twins. Methods A retrospective study was conducted on 290 premature cases out of 363 twin pregnancies who delivered alive babies in the First Affiliated Hospital, Sun Yat-sen University from September 2012 to March 2015. The selected cases, including 219 cases of DCDA and 71 cases of MCDA,were divided into three groups according to their gestational age at delivery: 28-31+6, 32-33+6and 34-36+6weeks. The clinical features, causes and risk factors were described between these three groups. Analysis of variance,Chi-square test and multi-variant Logistic regression were used for statistical analysis. Results The incidence of premature delivery in twin pregnancies was 79.9% (290/363), while this figure was lower in DCDA twins than in MCDA [76.3%(219/287) vs 93.4%(71/76),χ2=10.955,P=0.001]. The three leading causes of preterm birth in DCDA twins were gestational age≥36 weeks (33.8%, 74/219), preterm labor (30.6%, 67/219) and preterm premature rupture of membrane (PPROM) (8.7%, 19/219), while in MCDA twins were preterm labor (31.0%, 22/71), selective intrauterine growth restriction (21.1%, 15/71) and gestational age≥36 weeks (19.7%, 14/71). Logistic regression analysis showed that the independent risk factors of preterm birth in twins at 28-31+6weeks was PPROM (OR=2.390, 95%CI: 1.006-5.872,P=0.043), and for those twins at 32-33+6weeks, the independent risk factors were MCDA (OR=2.758, 95%CI: 1.243-6.118,P=0.013), preeclampsia (OR=12.176, 95%CI:4.685-31.642,P=0.000), PPROM (OR=5.348, 95%CI: 2.151-13.294,P=0.000) and preterm labor (OR=3.274, 95%CI:1.453-7.375,P=0.004). MCDA (OR=3.666, 95%CI: 1.364-9.585,P=0.010) and preeclampsia (OR=8.086, 95%CI:1.044-62.617,P=0.045) were the risk factors in the group of 34-36+6weeks. Conclusions Although preterm birth in MCDA and DCDA twins is due to different reasons, the former has a higher incidence than the latter. The risk factors of premature delivery at different gestations are also different. Key words: Pregnancy, twin; Premature birth; Risk factors