(360) Cerebroplacental Doppler ratio for the prediction of adverse perinatal outcomes in late-onset fetal growth restriction

Late-onset fetal growth restriction (LO-FGR), defined as onset ³ 32 weeks gestation, is the more common subgroup of FGR. The umbilical artery Doppler is usually unaffected. There are no subgroup-specific guidelines for monitoring pregnancies affected by LO-FGR. We compared the utility of the cerebro-placental Doppler ratio (CPR) to the Biophysical Profile (BPP), a widely endorsed FGR monitoring tool, for the prediction of adverse perinatal outcomes (APO).

Study Design: This is a retrospective cohort study of LO-FGR, defined as estimated fetal weight < 10^th%, from 2013-2018. Using logistic regression analysis, we determined whether low CPR < 5^th% and BPP score £ 6 significantly independently predicted the composite APO defined as one or more complications: cord pH < 7.20, 5-minute Apgar score of < 5, operative or cesarean delivery secondary to non-reassuring fetal heart tracing, assisted respiration at birth, NICU admission, and/ or perinatal death. Secondarily, we also evaluated prediction of severe neonatal morbidity (SNM) defined in Table 1 (legend).

Results: There were 233 cases of LO-FGR of which 76 (34%) had a low CPR percentile and 28 (13%) had a low BPP score. There were 22 (9.9%) cases with SNM of which 5 (2.1%) had a low CPR percentile and 4 (1.8%) had a low BPP score. A low CPR was associated with a significantly higher rate of individual and composite APO than cases with normal CPR percentile (p < 0.001) [Table 1]. Both a low CPR percentile and a low BPP score significantly predicted APO overall. CPR appeared to be a better predictor of the APO, controlling for gestational age at testing [Table 2]. Only BPP significantly predicted SNM: CPR (OR = 4.64, p = 0.13) and BPP (OR = 4.11, p = 0.038).

Conclusion: A low CPR percentile was a significant independent predictor of perinatal complications in LO-FGR, including abnormal fetal heart rate tracing, smaller birthweight percentile, and NICU admission. CPR appeared superior to BPP overall. CPR should be considered as a fetal surveillance tool in LO-FGR.