Chorioamnion separation as a risk for preterm premature rupture of membranes after laser therapy for twin-twin transfusion syndrome.

Abstract

To compare the outcomes in chorioamnion membrane separation with nonchorioamnion membrane separation cases after fetoscopic laser photocoagulation of placental anastomoses for the treatment of twin to twin transfusion syndrome. We performed a retrospective cohort study of twin to twin transfusion syndrome cases that underwent laser ablation at the Texas Children's Fetal Center from October 2007 to March 2009. The cases were identified from our database. We excluded triplet pregnancies. Chorioamnion membrane separation was identified by ultrasound examination performed within 24 hours of intervention. Preterm premature rupture of membranes (PROM) was defined as rupture of the membranes before 34 weeks of gestation. Ninety-seven cases were included in the analysis; 19 (19.6%) had chorioamnion membrane separation. There were no significant differences in preoperative and intraoperative variables, except for a lower recipient maximum vertical pocket (10.3+/-2.1 compared with 12.6+/-3.4; P<.01), and higher rate of iatrogenic septostomy (21% compared with 2.5%; P=.01) in the chorioamnion membrane separation group. Postoperatively, the incidence of preterm PROM was 74% in chorioamnion membrane separation group compared with 23% in the nonchorioamnion membrane separation group (relative risk 3.2, 95% confidence interval 1.9-4.4). The procedure-to-delivery interval was reduced by 20 days in the chorioamnion membrane separation group (P<.01). The neonatal survival rate was 63.2% in the chorioamnion membrane separation group compared with 84% in the nonchorioamnion membrane separation group (P=.016). A low preoperative recipient maximum vertical pocket is associated with increased risk of chorioamnion membrane separation. Postoperative chorioamnion membrane separation after laser surgery for twin to twin transfusion syndrome is a major risk factor for preterm PROM, early delivery, and an increase in perinatal mortality. II.