Vascular malperfusion and abruption are prevalent in placentas from pregnancies with congenital heart disease and not associated with cardiovascular risk.

Congenital heart disease (CHD) in pregnancy is associated with an increased risk of adverse maternal, obstetric, and neonatal outcomes, plausibly through mechanisms involving abnormal placental development and function. This retrospective study aims to elucidate how maternal CHD influences placental health. Demographic and clinical information were collected via electronic medical record review, and placentas underwent histopathological evaluation. Fifty-three singleton pregnancies were included: 35 participants (66%) were classified as lower cardiovascular risk (modified World Health Organization Classification (mWHO) I, II, II-III), and 18 (34%) were classified as higher cardiovascular risk (mWHO III, IV). 12 participants (23%) had a fetus with small for gestational age (SGA). Maternal vascular malperfusion (53%) and placental abruption (11.6%) were common in this cohort, with prevalence above baseline risk. Participants at higher cardiovascular risk had higher rates of SGA (p = 0.04), subchorionic hematomas (p = 0.01) and birth weight:placental weight < 10th percentile (p = 0.04), but did not differ in rates of maternal vascular malperfusion (p = 0.15) compared to those at lower cardiovascular risk. In pregnancies with maternal CHD, SGA and histologic evidence of maternal vascular malperfusion and placental abruption were common, though patients at higher cardiovascular risk did not show evidence of worsened placental health compared to those at lower risk.