226 Second trimester cerebroplacental ratio as a predictor of adverse perinatal outcomes

Abstract

An abnormal cerebroplacental ratio in the third trimester is associated with adverse perinatal outcome. However, little is known about the implication of an abnormal cerebroplacental ratio in the second trimester. The objective of this study is to evaluate the relationship between second trimester cerebroplacental ratio and adverse perinatal outcome. This retrospective cohort study in a single tertiary referral center utilized data from all non-anomalous singleton pregnancies that underwent Doppler assessment of the cerebroplacental ratio between 20 and 28 weeks gestation. The study period was January 1, 2015 to July 31, 2018. Abnormal cerebroplacental ratio was defined as less than 5th percentile for gestational age. The primary outcome was a composite of adverse perinatal outcomes that included preterm delivery, a small for gestational age neonate, and neonatal intensive care unit (NICU) admission. Urgent delivery for fetal distress (operative vaginal or cesarean section) was a secondary outcome. 2326 pregnancies met inclusion criteria. Of these, 91 (3.9%) had an abnormal second trimester cerebroplacental ratio. Fetuses with an abnormal second trimester cerebroplacental ratio had a 2.3-fold (95% CI 1.5-3.6, p<.0005) increased risk of adverse perinatal outcome after adjusting for potential confounders such as chronic hypertension, pregestational diabetes, and smoking during pregnancy. Fetuses with an abnormal second trimester cerebroplacental ratio had a 2.8-fold (95% CI, 1.7-4.6; p<0.0001) increased risk of prematurity, after adjusting for confounders. An abnormal second trimester cerebroplacental ratio was also associated with a 1.9-fold (95% CI 1.1-3.5, p<0.05) increased risk of urgent delivery for fetal distress. In a subgroup analysis of appropriate for gestational age fetuses, an abnormal cerebroplacental ratio was associated with a significantly increased risk of preterm delivery and NICU admission after controlling for maternal comorbidities. An abnormal second trimester cerebroplacental ratio may predict adverse perinatal outcome.