A retrospective study of mid-trimester rupture of the membranes: Irish perspective from a tertiary unit following change of termination of pregnancy legislation.

OBJECTIVE: Mid-trimester premature prelabor rupture of membranes between 14+0-23+6 gestation age is a rare complication of pregnancy associated with poor maternal and fetal outcomes. Since the Health (Regulation of Termination of Pregnancy) Act, 2018, termination of pregnancy (TOP) can be offered after 12+0 gestational age where there is a risk to the "life or health" of the woman or where the fetus is "likely to die within 28 days of life." Prior to 2018, termination was illegal except in circumstances of immediate threat to the life of the mother. This legislative change means that accurate data were critical for counseling families. The aim of the present study was to describe the maternal and neonatal outcomes following mid-trimester premature prelabor rupture of membranes (MTPPROM) and to examine neonatal outcomes in relation to deepest vertical pool and gestational age at diagnosis.

METHODS: To compare data to a similar historic Irish study conducted prior to liberalization of the termination legislation. This study measured outcomes at a tertiary referral center in Ireland with approximately 7400 deliveries per annum. It was a retrospective cohort study of consecutive MTPPROM from January 2019 to February 2024 in an Irish tertiary hospital with complete data collection made possible by the electronic healthcare record.

RESULTS: Of the 37 488 women delivered at this center during the study period, 87 (0.2%) patients met the inclusion criteria. The median (interquartile range [IQR]) maternal age was 33 (26-40), with a mean (standard deviation [SD]) body mass index (BMI) of 27.54 (+/-5.8). Median (IQR) gestational age at MTPPROM was 21+0 (17-25). The median (IQR) latency period was 11 days (32). A maternal morbidity was experienced in 62% (54/87) of patients, most commonly chorioamnionitis (37.9%, 33/87), postpartum hemorrhage (18.4%, 16/87) and manual removal of placenta (17.2%, 15/87). There was a higher percentage of manual removal of placenta and postpartum hemorrhage in the conservative management group compared to those who opted for termination of pregnancy. There were no maternal mortalities. There were 28 intrauterine deaths (30.8%, 28/91). There were 63 livebirths (69.2%, 63/91) of which 26 survived to discharge, at a survival to discharge rate of 28.6% (26/91). These outcomes were compared to a study prior to the Health Act 2018 showing a neonatal survival rate of 5%. All neonates born to this cohort of patients experienced morbidity (n = 26, 100%). Prenatal ultrasound diagnosis of anhydramnios was associated with an extremely poor prognosis, with only 35.3% (6/17) live births of whom none survived to discharge. Pregnancies with deepest vertical pool <2 cm had a lower neonatal survival rate compared to those with deepest vertical pool >2 cm (16.1%, 9/56 vs. 43.8%, 14/32, P = 0.004). There was a higher survival to discharge rate when diagnosis was over 20/40 gestation (42.3%, 22/52 vs. 8.3%, 4/48, P = 0.0001), with 84.6% (22/26) of those surviving to discharge diagnosed as MTPPROM after 20 weeks' gestation.

CONCLUSION: The major maternal morbidity rate in MTPPROM following liberalization of the termination legislation was 62% (54/87), with no maternal mortalities. The neonatal survival rate was 28.6% (26/91). There was a higher survival rate when diagnosis was over 20/40 gestation and deepest vertical pool >2 cm. Through the liberalization of TOP, the cases with poorer prognosis now have the option of ending their pregnancies.