Rupture of membranes before the age of viability and birth after the age of viability: comparison of outcomes in a matched cohort study.

OBJECTIVE: To compare composite adverse outcome rate of infants <32 weeks gestational age (GA) who were born after preterm premature rupture of membranes (PPROM) at previable gestation to those born without PPROM.

STUDY DESIGN: Retrospective review of prospective collected data for infants discharged between 2004 and 2007 was conducted. Cases were infants with >7 days of PPROM that occurred before 24 weeks. Matched cohort consisted of infants born without PPROM (matched for GA, sex and admission date). Composite adverse outcome was assessed considering death or any of the following three severe morbidities (severe neurological injury, severe retinopathy of prematurity or chronic lung disease).

RESULT: The 29 cases had higher mean severity of illness score compared with 74 matched infants. Mean duration of ROM was 45 vs 2 days and mean GA at the ROM was 21 vs 27 weeks, respectively. Logistic regression confirmed significantly higher risk of composite adverse outcome rates for cases (69 vs 47%; P=0.02, adjusted odds ratio 4.0, 95% CI 1.2, 13.6).

CONCLUSION: The survival rate for infants born at <32 weeks following PPROM at previable age has improved significantly; however, these infants had a higher rate of adverse composite neonatal outcome.