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 and fetal growth. Demographic and clinical information were collected via electronic medical record review and placentas underwent histopathological evaluation. Fifty-three singleton pregnancies over the study period were included: 23 (43%) participants were classified as lower cardiovascular risk (modified World Health Organization (mWHO) I, II) and 30 (57%) were classified as higher cardiovascular risk (mWHO II-III, III, IV) using the modified WHO classification. 12 participants (23%) had a fetus with small for gestational age (SGA). Maternal vascular malperfusion (53%), placental abruption (11.6%), and evidence of infection (26%) were common in this cohort, with prevalence above baseline risk. Participants with mWHO I or II did not significantly differ in placental findings compared to those with mWHO II-III, III, or IV (p>0.05). In pregnancies with maternal CHD, SGA and histologic evidence of maternal vascular malperfusion, and placental abruption were common, though patients with higher cardiovascular risk (mWHO II-III, III, IV) did not show evidence of worsened placental health or fetal growth compared to those with lower risk (mWHO I, II).