1193-P: GDM Treatment, Diagnosis Timing, and Glycemic Control—Associations with Newborn Outcomes in the SWIFT Study

Suboptimal glycemic control in GDM increases risk of adverse perinatal outcomes. We evaluated GDM treatment type (glyburide vs diet), timing of diagnosis (<20w gestation: early (E) vs. >20w: standard (S), glycemic control (optimal vs suboptimal), and perinatal outcomes. In a diverse cohort of 902 GDM mother-infant dyads (77% Hispanic, Asian, or Black; 23% White), prenatal glycemic control was measured by self-home glucose monitoring and categorized as optimal (≥80% of tests met target, fasting glucose ≤95 mg/dL and 1h post-prandial ≤140 or 2h ≤120) or suboptimal (<80% of tests met target). Compared to the S diagnosis and diet treatment group, the E diagnosis and glyburide treatment group was older, more likely to have prior GDM, and higher prepregnancy BMI and glucose levels on the 3h 100 g prenatal OGTT. Glyburide treatment was associated with suboptimal control (P<0.001). Multivariable logistic regression estimated odds ratios (OR, 95%CI) of perinatal outcomes associated with GDM treatment type, timing of diagnosis, and glycemic control vs. the referent group with S diagnosis and optimal control on diet treatment alone, adjusted for pre-pregnancy BMI, infant sex and gestational age. Among E and S diagnosis groups with suboptimal control both before and after glyburide treatment, ORs, 95%CI were higher for neonatal length of stay ≥3 days: (E 3.6, 1.6-8.1; S 2.0, 1.1-3.6), neonatal hypoglycemia (E 2.4, 1.0-5.9; S 1.9, 1.0-3.6) and large-for-gestational age (LGA) birthweight (E 4.1, 1.8-9.1; S 2.8, 1.6-4.9). For E diagnosis with suboptimal control before, and optimal control after glyburide, the odds of LGA were elevated (2.8, 1.2-6.6) similar to the S diagnosis with suboptimal control after glyburide. Associations did not affect Cesarean delivery or NICU admission. These findings show that even with post-glyburide optimal glycemic control, odds of LGA development associated with exposure to GDM from early gestation may be only partially ameliorated by glyburide treatment.