Congenital Malformation Risk According to Hemoglobin A1c Values in a Contemporary Cohort with Pregestational Diabetes.

Objective The study aimed to evaluate the association between hemoglobin A1c values and likelihood of fetal anomalies in women with pregestational diabetes. Study Design Women with pregestational diabetes who delivered at a single institution that serves a nonreferred population from May 1, 2009 to December 31, 2018 were ascertained. Hemoglobin A1c values were obtained at the first prenatal visit. Women who delivered a singleton live- or stillborn infant with a major malformation as defined by European Surveillance of Congenital Anomalies criteria were identified. In infants with multiple system anomalies, each malformation was considered separately. Hemoglobin A1c values were analyzed categorically by using Mantel–Haenszel method and continuously with linear regression for trend for fetal anomalies. Results A total of 1,676 deliveries to women with pregestational diabetes were delivered at our institution, and hemoglobin A1c was assessed in 1,573 deliveries (94%). There were 129 deliveries of an infant with at least one major malformation, an overall anomaly rate of approximately 8%. Mean hemoglobin A1c concentration was significantly higher in pregnancies with anomalous infants, 9.3 ± 2.1% versus 8.0 ± 2.1%, and p Conclusion In women with pregestational diabetes, hemoglobin A1c is strongly associated with fetal anomaly risk. Data from a contemporary cohort may facilitate counseling and also highlight the need for preconceptual care and glycemic optimization prior to entry to obstetric care. Key Points