Association of maternal pre-pregnancy diabetes and gestational diabetes with congenital anomalies of the newborn

Methods: We included 29,211,974 live births with maternal age ranged from 18 to 49 years old documented in the National Vital Statistics System in the United States, 2011-2018. Information on pre-pregnancy diabetes, GDM, and congenital anomalies was retrieved from birth certificates. Log-binomial regression was used to estimate risk ratios (RRs) and 95% confidence intervals (CIs) for congenital anomalies overall and by subtypes.

Results: Of the 29,211,974 births, there were 90,061 infants who had congenital anomalies identified at birth. The adjusted RRs of congenital anomalies at birth were 2.44 (95% CI, 2.33-2.55) for pre-pregnancy diabetes and 1.28 (95% CI, 1.24-1.31) for GDM. The association were generally consistent across subgroups by maternal age, race/ethnicity, pre-pregnancy obesity status, and infant sex. For specific subtypes of congenital anomalies, maternal pre-pregnancy diabetes or GDM was associated with an increased risk of most subtypes. For example, the adjusted RRs of cyanotic congenital heart disease were 4.61 (95% CI, 4.28-4.96) for pre-pregnancy diabetes and 1.50 (95% CI, 1.43-1.58) for GDM; the adjusted RRs of hypospadias were 1.88 (95% CI, 1.67-2.12) for pre-pregnancy diabetes and 1.29 (95% CI, 1.21-1.36) for GDM.

Conclusion: Pre-pregnancy diabetes and, to a lesser extent, GDM were associated with several subtypes of congenital anomalies of the newborn. These findings suggest potential benefits of preconception counseling in women with pre-existing diabetes or at risk of GDM for the prevention of congenital anomalies.