Cardiomyopathy and cardiomegaly in stillborn infants of diabetic mothers.

To report the incidence of cardiomegaly in stillborn normally formed infants of mothers with diabetes mellitus. This is a retrospective study with institutional ethics approval. The presence of cardiomegaly was recorded in stillborn infants of diabetic mothers (N = 27) and compared with that recorded in stillborn large-for-gestational age (LGA > 90th percentile, n = 18) and stillborn appropriately grown (10th to 90th percentiles, n = 107) nondiabetic infants. Blinded to the clinical details, the histology slides were reviewed to measure cardiac wall thickness and to record the presence or absence of myocardial fiber disarray. Stillborn infants of mothers with diabetes mellitus, when compared with appropriately grown stillborn nondiabetic infants and when adjusted for birth weight, had heavier hearts, thicker ventricular free wall measurements, and lighter brains. While cardiomegaly was reported in 22% of stillborn LGA infants, comparison with stillborn appropriately grown infants revealed no difference in heart weights corrected for birth weight. Comparison of LGA nondiabetic infants with stillborn diabetes mellitus infants revealed greater actual heart weight/expected for birth weight (P < 0.05) and lighter brains (actual brain weight/expected for birth weight, P < 0.05) in the diabetes mellitus group. Cardiomegaly is a common finding in stillborn infants of mothers with diabetes mellitus and may contribute to the risk of fetal death in these pregnancies.