Midchildhood Obesity After Exposure to Gestational Diabetes Mellitus: The SWIFT Study in Youth

OBJECTIVE To assess how treatment type, diagnosis timing, and meeting of glycemic targets in gestational diabetes mellitus (GDM) affect childhood obesity risk. RESEARCH DESIGN AND METHODS This study included 809 mothers with GDM, treated with diet or glyburide, who enrolled at 6–9 weeks postdelivery in a prospective cohort (2008–2011) and their children who had a BMI measurement between ages 5 and 11 years, after exclusion of mothers with diabetes diagnosis postdelivery. Mothers’ GDM diagnosis timing (early 24 weeks gestation vs. standard ≥24 weeks), treatment type, and meeting of self-monitored glycemic targets, along with children’s weight and height at ages 5–11 years, were obtained from Kaiser Permanente Northern California electronic health records. Log-binomial regression models estimated adjusted relative risks (aRRs) and 95% CIs of childhood obesity, adjusting for covariates including glycemic targets and maternal prepregnancy BMI. RESULTS Participants were multiethnic (77% Asian, Black, or Hispanic), with a mean (SD) prepregnancy BMI of 29.4 (7.2) kg/m2. GDM was diagnosed early (24 weeks) in 20%, glyburide treatment was provided to 27%, and glycemic targets were met by 70% of participants. Child BMI percentiles were obtained at a mean (SD) age of 9.5 (1.5) years (58% normal weight, 17% overweight, and 25% obese). In a joint analysis of GDM treatment type and diagnosis timing, compared with standard diagnosis and dietary treatment (referent), the aRR (95% CI) of childhood obesity was 1.58 (1.19–2.12) with early diagnosis and glyburide treatment and 1.53 (1.15–2.04) with early diagnosis and dietary treatment. CONCLUSIONS Children exposed to GDM diagnosed before the standard time frame of 24 weeks, regardless of treatment type, meeting of glycemic targets, or maternal prepregnancy BMI, are more likely to develop obesity up to 11 years later.