Maximum vertical pocket versus amniotic fluid index: assessing adverse pregnancy outcomes in patients with polyhydramnios

To estimate the association of polyhydramnios detected by either maximum vertical pocket (MVP) or amniotic fluid index (AFI) or both and adverse maternal, fetal and neonatal outcomes. We hypothesized that polyhydramnios detected by both measures is more strongly associated with adverse outcome, and specifically fetal demise or neonatal death, when compared to either alone. Secondary analysis of a prospective study of ultrasound assessment of amniotic fluid volume in over 13,000 singleton pregnancies enrolled between 6/1/2014 – 5/31/2021. We defined polyhydramnios as MVP of >8 cm and/or AFI of >24 cm. Discordant polyhydramnios was defined as meeting criteria for polyhydramnios by AFI or MVP but not both. Concordant polyhydramnios was defined as meeting criteria by both AFI and MVP. We built modified Poisson regression models to examine associations between discordant polyhydramnios, concordant polyhydramnios, and adverse outcomes. Adverse outcomes included NICU admission, fetal demise or neonatal death, cesarean section (CS), meconium-stained fluid, premature rupture of membranes (PROM), and/or cord prolapse (Table 1). All models were adjusted for maternal age, smoking status, diabetes, birthweight, and fetal growth restriction. Compared to those with a normal AFI and MVP, participants with polyhydramnios by either AFI or MVP were significantly more likely to be delivered by CS, have an infant admitted to the NICU, or undergo fetal or neonatal death (Table 1). These differences persisted in adjusted models (Table 2). Polyhydramnios detected by both measures (MVP and AFI) is more strongly associated with adverse outcomes including NICU admission, cesarean section, and most significantly fetal demise or neonatal death when compared to that detected by one measure alone.View Large Image Figure ViewerDownload Hi-res image Download (PPT)