OBJECTIVE: The purpose of our study was to investigate the incidence of chorioamniotic membrane separation (CMS) after fetoscopic laser surgery and the association between CMS and preterm premature rupture of membranes (pPROM). We also analyzed the risk factors associated with the occurrence of CMS. METHOD: Retrospective cohort study of 148 patients with twin-twin transfusion syndrome who underwent laser surgery at our institution from March 2003 to December 2009. RESULTS: Chorioamniotic membrane separation occurred in 29 of 148 (19.6%) patients. The presence of CMS strongly correlated with pPROM prior to 28 weeks' gestation. Multivariate analysis of the risk factors of pPROM <28 w showed for CMS an odds ratio (OR) of 7.01 (95% confidence interval (CI): [1.46; 33.60], p = 0.015). Posterior placentation correlated with the occurrence of CMS (OR: 4.17, 95% CI: [1.39; 12.49], p = 0.01) and the recipient's deepest vertical pocket (OR: 1.38, 95% CI: [1.03; 1.86], p = 0.03). There was however no measurable impact of CMS on gestational age at delivery, neither on survival. CONCLUSION: Chorioamniotic membrane separation occurs in approximately 20% of patients following fetoscopic laser surgery for twin-twin transfusion syndrome and is associated with pPROM <28 w. Posterior location of the placenta coincided with an elevated risk for CMS.
OBJECTIVE: The purpose of our study was to investigate the incidence of chorioamniotic membrane separation (CMS) after fetoscopic laser surgery and the association between CMS and preterm premature rupture of membranes (pPROM). We also analyzed the risk factors associated with the occurrence of CMS. METHOD: Retrospective cohort study of 148 patients with twin-twin transfusion syndrome who underwent laser surgery at our institution from March 2003 to December 2009. RESULTS: Chorioamniotic membrane separation occurred in 29 of 148 (19.6%) patients. The presence of CMS strongly correlated with pPROM prior to 28 weeks' gestation. Multivariate analysis of the risk factors of pPROM <28 w showed for CMS an odds ratio (OR) of 7.01 (95% confidence interval (CI): [1.46; 33.60], p = 0.015). Posterior placentation correlated with the occurrence of CMS (OR: 4.17, 95% CI: [1.39; 12.49], p = 0.01) and the recipient's deepest vertical pocket (OR: 1.38, 95% CI: [1.03; 1.86], p = 0.03). There was however no measurable impact of CMS on gestational age at delivery, neither on survival. CONCLUSION: Chorioamniotic membrane separation occurs in approximately 20% of patients following fetoscopic laser surgery for twin-twin transfusion syndrome and is associated with pPROM <28 w. Posterior location of the placenta coincided with an elevated risk for CMS.