Measures of Fetal Growth and Cardiac Structure in Stillbirths With Placental Maternal Vascular Malperfusion: Evidence for Heart Weight Sparing and Structural Cardiac Alterations in Humans.

Background: Placental maternal vascular malperfusion (MVM) is associated with fetal growth restriction (FGR). While FGR increases the risk of cardiovascular disease, the impact of MVM on fetal cardiac structure is understudied.

Methods: We utilized a cohort of autopsied stillbirths; 29 with MVM as the cause of death and 21 with a cause of death unrelated to MVM. Fetal and organ weights and heart measurements were standardized by gestational age and compared between MVM and non-MVM stillbirths. Differences in standardized fetal organ and cardiac measures as compared to standardized fetal body weight were calculated to account for body size.

Results: MVM stillbirths had smaller organ and heart weights than non-MVM stillbirths; however, after accounting for gestational age, heart weight was the least affected among all organs. In an analysis of organ weights relative to body size, heart weights were 0.31 standard deviations (SD) larger than expected relative to body weight (95% CI: 0.04, 0.57). Right and left ventricle thicknesses and mitral valve circumference were also larger than expected relative to body weight.

Conclusion: Stillbirth due to MVM was associated with relative sparing of heart weight and other heart measurements. The significance of these findings in liveborn infants needs further study.