Birth and first-year outcomes in infants of mothers with familial hypercholesterolemia or atherosclerotic cardiovascular disease in the US: A retrospective cohort study.

BACKGROUND: Infant outcomes among those born to mothers with familial hypercholesterolemia (FH) or atherosclerotic cardiovascular disease (ASCVD) remain unclear. OBJECTIVE: To assess outcomes among infants of mothers living with FH or ASCVD in the US. METHODS: In this retrospective claims-based cohort study, mother-infant singleton pairs (2018-2023) were identified. Infants were followed to death, disenrollment, age 1 year, or the end of 2024. Exposure was classified as maternal prepregnancy diagnosis of FH or ASCVD. Outcomes included preterm birth, low birth weight, macrosomia, neonatal intensive care unit (NICU) admission, major congenital malformations (MCM), infant mortality, and healthcare utilization at 1 year of age. Inverse probability treatment weighting was utilized to compare the FH and ASCVD cohorts with a reference cohort, respectively. RESULTS: Among 275 FH, 878 ASCVD, and 348,683 reference mother-infant pairs, the use of maternal lipid-lowering therapies was rare and declined during pregnancy. No increased risks of adverse outcomes were observed for the FH cohort vs the reference cohort. In contrast, the ASCVD cohort had higher risks of preterm birth (adjusted risk ratio, 1.73 [95% CI, 1.40-2.12]), low birth weight (1.77 [1.28-2.46]), NICU admission (1.48 [1.23-1.77]), and noncardiac MCM (1.58 [1.05-2.37]) than the reference cohort. At 1 year of age, the ASCVD cohort also had higher risks of inpatient admissions, emergency department visits, and urgent care clinic visits. CONCLUSION: Infants of mothers living with ASCVD-but not those with FH-had higher risks of adverse birth outcomes and increased healthcare utilization.