1241-P: Pharmacologic Treatment of GDM and Perinatal Outcomes

Medical nutritional therapy is the recommended initial treatment for GDM, but 30-50% of patients with GDM require the addition of pharmacologic therapy. Insulin is the only pharmacologic treatment recommended by the American Diabetes Association. However, oral agents have several advantages over insulin including cheaper cost, greater ease of use, and adherence among patients. ACOG recognizes that clinical situations may necessitate the use of oral agents and suggests metformin (and possibly glyburide) as a reasonable alternative. We examined the association between GDM pharmacologic treatment and perinatal outcomes in a large and racially diverse cohort of GDM pregnancies livebirths between 2008 and 2021 (n = 19,903) in Kaiser Permanente Northern California. GDM was defined based on laboratory glucose values and/or clinician diagnosis. We used modified poisson regression to estimate risk ratios. Overall, 75% were prescribed glyburide, 8% Metformin, and 17% insulin only. Compared to GDM pregnancies initiated on Insulin, pregnancies initiated on Glyburide had a 17% reduced risk of Preterm birth [risk ratio[RR]: 0.83 (0.75 - 0.92) and a 12% reduced risk of having a small for gestational age infant [RR: 0.88 (0.77 - 0.99)] and no association with having a large for gestational age infant [0.97 (0.90 - 1.04)] adjusting for age, pre-pregnancy BMI, race/ethnicity, and parity. Compared to GDM pregnancy initiated on Insulin, pregnancies initiated on Metformin were associated with an 18% reduced risk of preterm birth [risk ratio: 0.82 (RR: 0.69 - 0.98)], a 28% reduction in large for gestational age [adjusted relative risk: 0.72 (RR: 0.63 - 0.82)], and no association with small for gestational age infant [0.97 (RR: 0.80 - 1.18)] in adjusted models. These findings suggest that oral agents may be associated with a lower risk of perinatal complications. Future work needs to address possible confounding due to disease severity.