Prenatal Congenital Heart Disease and Placental Phenotypes: Preserved Neonatal Weight Despite Small Placentas

Background: Congenital heart disease (CHD) affects 8 in 1,000 live births with significant postnatal implications including growth failure, neurodevelopmental delay, and mortality. The placenta develops concomitantly with the fetal heart. High rates of placental pathology and discordant growth in pregnancies affected by CHD highlight the significance of the fetal-placental-cardiac axis.

Objectives: This study aimed to characterize the relationship between neonatal birthweight (BW), head circumference, placental weight (PW), and placental pathology in pregnancies affected by CHD. PW:BW provides a surrogate to assess placental efficiency, or nutrient exchange and delivery by the placenta, across CHD phenotypes.

Methods: Retrospective cohort of 139 live-born singletons with postnatally confirmed CHD with placental pathology. Placental examination, infant BW, head circumference, and CHD categories (septal defects, right-sided defects, left-sided defects, conotruncal anomalies, and others) were included. Chi-square, Fisher's exact, or Kruskall-Wallis tests and multinomial logistic regressions, as appropriate.

Results: Median birthweight and head circumference percentile was 33 and 35, respectively. Placental pathology was documented in 37% of cases. PW to BW ratios were <10th percentile for 78% and <3rd percentile for 54% of the cohort, with no difference between CHD categories ( = 0.39 and  = 0.56, respectively).

Conclusions: Infants with CHD have preserved BW and head circumferences in the setting of small placentas and increased prevalence of placental pathology, suggesting placental efficiency. Detection of abnormal placental growth could add prenatal diagnostic value. Placental and neonatal discordant growth may allude to a vascular anomaly predisposing fetuses to developing CHD. Further studies are needed to explore fetal nutrient delivery and utilization efficiency.