120: The role of serial amniotic fluid volume measurements in pregnancies complicated by preterm premature rupture of membranes in predicting neonatal respiratory outcome

Abstract

Early fetal lung development is dependent on the presence of a sufficient amount of amniotic fluid. We aimed to evaluate the role of serial AFV assessments in pregnancies complicated by early preterm premature rupture of membranes (PPROM) in predicting neonatal respiratory outcome. Retrospective study of all women with a singleton pregnancy admitted to a single tertiary referral center with PPROM between 20 and 28 6/7 weeks of gestation during 2004- 2014 and underwent expectant management. According to our institutional protocol, each patient underwent an AFV assessment at presentation followed by biweekly assessment of AFV until delivery. In the current analysis, we included only patients that underwent ≥ 4 serial AFV measurements. Pregnancies complicated by delivery at <23 weeks or major fetal anomalies were excluded. We compared pregnancy and neonatal outcome between four groups of women based on the proportion of sonographic exams documenting oligohydramnios (defined as maximal vertical pocket <2cm): 0-25% (group A), 26-50% (group B), 51-75% (group C) and 76-100% of studies (group D). Composite respiratory outcome was defined as any of the followings: bronchopulmonary dysplasia, pulmonary hypoplasia, or respiratory distress syndrome. A total of 268 women who underwent 1512 AFV studies met the study criteria. Mean gestational age at PPROM was 25.8 ± 1.7 weeks and the mean latency to delivery was 19.6 ± 11.4 days. The proportion of women classified as groups A, B, C or D were 74 (27.6%), 77(28.7%), 35 (13.1%), and 82 (30.6%) respectively. The overall rate of composite respiratory outcome was 133/268 (49.6%). The rate of composite respiratory outcome did not differ between the 4 groups (40.5%, 48.1%, 54.3%, 57.3% for groups A-D, respectively, all non-significant). In an adjusted analysis, various factors, but not the AFV group, were associated with the risk of composite neonatal respiratory outcome (Table). We did not find evidence that the information obtained from serial AFV measurements is useful for the prediction of neonatal respiratory outcome in pregnancies complicated by early PPROM. Therefore, the role of costly and time-consuming serial sonographic assessment in women with PPROM should be reevaluated.