493: Periconception HbA1c and congenital anomalies in a racially diverse cohort of women with pregestational diabetes

Abstract

Studies examining the association between periconception hemoglobin A1c (HbA1C) and fetal anomalies are largely among white, non-Hispanic women with type 1 diabetes mellitus (DM) and do not reflect the current U.S. epidemiology of pregestational DM. Thus, we assessed the relationship between periconception HbA1C and fetal anomalies in a diverse population of women with pregestational DM. Retrospective cohort study of all pregnant women with pregestational DM at a single tertiary institution (1/03-1/17) whose pregnancies reached at least 20 weeks’ gestation. The primary outcome was frequency of major or minor congenital anomalies as assessed by ultrasound, pathology, and newborn examination (excluding known aneuploidy). Periconception HbA1C, defined as HbA1C within three months of conception, was assessed as a continuous variable and by category (HbA1C ≤ 7.4%, 7.5 – 9.4%, 9.5 – 11.4%, and ≥ 11.5%). The association of HbA1C with anomalies was analyzed using bivariable and multivariable analyses. Of 416 eligible women with pregestational DM, 65.5% had type 2 DM and 29.8% were non-Hispanic black. Nearly 1 in 6 (16.5%) women had a fetal anomaly. The majority of anomalies (75.4%) were classified as major and almost half of those (47.4%) were cardiovascular. The median HbA1C of women with fetal anomalies was significantly greater than that of women without anomalies (8.2% vs. 6.6%, p<0.001). The adjusted odds of anomaly increased significantly with each percentage point increase in HbA1c (aOR 1.47; 95% CI 1.27-1.69). Women with HbA1C ≥ 11.5% had a nearly 45% frequency of any anomaly (Figure) and significantly increased adjusted odds of anomalies compared to women with HbA1c ≤7.4% (Table). Women with HbA1C 7.5-9.4% and 9.5-11.4% also demonstrated similarly high frequencies of anomalies (19.7% and 33.3%, respectively) (Table). Compared to women with the HbA1C ≤7.4%, women with HbA1C ≥11.5% were significantly more likely to be younger (RRR 0.92, 95% CI 0.85-0.99) and non-Hispanic black (RRR 13.23, 95% CI 2.66-65.80). In a diverse cohort of women with pregestational DM, higher periconception HbA1C is significantly associated with congenital fetal anomalies. The frequency of anomalies is higher than reported in older literature, and identified to be as high as nearly 1 in 2 women with the poorest glycemic control.View Large Image Figure ViewerDownload Hi-res image Download (PPT)