181-LB: Congenital Malformations and Medication Use in Women With Type 2 Diabetes—Preliminary Results

Background: Congenital malformations occur more frequently in pregnancies of women with type 2 diabetes, mainly attributed to poor glycemic control. However, using certain medications may also contribute. Aim: To describe medication use by conception time in women with type 2 diabetes.

Methods: In this retrospective cohort, women with singleton pregnancies from two tertiary care hospitals were enrolled. Data on maternal age, time of diabetes diagnosis, medication use, BMI, HbA1c, and congenital malformations were collected from medical records between May 2005 and June 2021. We excluded four neonates with genetic/chromosomic diseases. Poisson regression with robust estimates was used to evaluate risk factors for congenital malformations.

Results: We included 634 women; 212 (33.5%) presented overt diabetes; 136 (21.5%) arrived at prenatal care in the first trimester; 18 (2.8%) had a miscarriage; 560 (88.3%) delivered alive newborns, and 17 (2.7%), stillbirth. Only 227 women (35.8%) had an HbA1c measured in the first trimester, and 304 (48.6%) had an HbA1c before 28 weeks of gestation. Congenital malformations were diagnosed in 77 (13.7%) neonates; of these, 56 (73%) were cardiac defects, isolated or combined with other malformations. Few women used folate in the first trimester (115; 18.1%), almost always introduced after pregnancy diagnosis; 353 (55%) used oral antidiabetics; 116 (18.3%), any anti-hypertensive medication, and 16 (2.5%), statins. In adjusted models including age, BMI and HbA1c, sulfonylurea was associated with increased risk of congenital malformation: RR 2.7, 95% CI 1.3-5.6, p=0.009, when HbA1c in the first trimester entered the model (n=200); and RR 1.64, 95% CI 1.0-2.6, p=0.038, with an HbA1c measured before 28 weeks (n=539).

Conclusion: In this cohort of women with type 2 diabetes, congenital malformations were more frequent than in the general population. Sulfonylurea was the only medication associated with an increased risk of congenital malformation.