Perinatal Outcomes and Influence of Amniotic Fluid Volume Following Previable, Preterm Prelabor Rupture of Membranes (pPPROM): A Historical Cohort Study

PURPOSE: To determine perinatal outcomes and influence of amniotic fluid volume in pregnancies complicated by previable, preterm prelabor rupture of membranes (pPPROM). PATIENTS AND METHODS: This was a historical cohort study from two tertiary-level maternity hospitals (January 1, 2009 to December 31, 2015). All pregnancies complicated by pPPROM were identified using ICD coding of discharge abstracts. Hospital charts were reviewed to collect maternal demographics, pregnancy and delivery events, and immediate postnatal outcomes (including survival). Post-processing review of stored ultrasound images was performed to evaluate the relationship between amniotic fluid volume and outcomes. RESULTS: A total of 113 pregnancies were eligible and 99 were included in the final analysis (74 with “expectant management” and 25 opting for elective termination). The median gestational age at pPPROM was 20+6 weeks [IQR 19+4 to 21+5]. For those choosing expectant management, the median latency between pPPROM and delivery was 7 days, median gestational at delivery was 23+1 weeks, and neonatal survival to discharge was 27.5% overall. There was a trend towards higher rates of pregnancy termination at one hospital (31.7%) compared to the other (15.4%), but no difference between sites with respect to latency, mode of delivery, or survival amongst those managed expectantly. There was a relationship between survival and gestational age at pPPROM (p<0.04), as well as initial amniotic fluid volume category: 52.6% of survivors had normal initial amniotic fluid volumes whereas the majority of previable losses had oligohydramnios and the majority of stillbirths had anhydramnios. CONCLUSION: After expectant management, more than one in four newborns following pPPROM survived to hospital discharge. While gestational age at rupture was most strongly correlated with survival, normal initial amniotic fluid volumes were mostly seen in survivors whereas stillbirths more frequently had anhydramnios. These findings will help to improve counseling and care of patients with pPPROM and in guiding long-term follow-up studies.