OBJECTIVES: Preterm premature rupture of membranes (PPROM) is a leading 
complication following fetoscopic laser coagulation (FLC) for twin-twin 
transfusion syndrome (TTTS). Our primary objective was to describe the impact of 
improvements in surgical technique on survival and rate of PPROM over time. The 
secondary objective was to assess potential risk factors for PPROM.
DESIGN AND SETTING: Single-centre retrospective observational study.
POPULATION: 1092 consecutive cases of TTTS operated by FLC between 2000 and 
2016, with a 6.8% rate of loss to follow up.
METHODS: The incidence of PPROM and potential risk factors were analysed using 
competing risks models.
MAIN OUTCOME MEASURES: PPROM, neonatal survival and neurological damage at 28 
days.
RESULTS: PPROM <32 weeks increased from 15 to 40% between 2000 and 2016 along 
with an overall improvement of perinatal outcomes: dual survival rose from 42 to 
66% whereas dual losses dropped two-fold, from 19 to 9%. Gestational age at 
surgery at <17 weeks was a significant risk-factor for PPROM, with an additional 
risk of 10% within the first week of surgery. Although early PPROM at <20 weeks 
carried a 56% risk of miscarriage, the occurrence of PPROM at >20 weeks did not 
affect survival, despite an increase in preterm birth at <32 weeks.
CONCLUSIONS: With significant improvement in perinatal outcomes, possibly 
related to improvements in surgical technique, postoperative complications have 
shifted to non-lethal obstetric complications such as PPROM, with rather 
reassuring postnatal outcomes, despite an increase in preterm birth and, 
potentially, morbidity. Early surgeries (<17 weeks) are at higher risk of 
postoperative PPROM.
TWEETABLE ABSTRACT: Following laser/TTTS, rates of PPROM increased with 
perinatal survival; surgeries at <17 weeks are at highest risk.