Maternal weight gain in women who develop gestational diabetes mellitus.

Objective: To assess maternal weight gain before 24 weeks in women developing gestational diabetes mellitus (GDM) compared with controls with normal glucose tolerance.

Methods: This was a retrospective cohort study of maternal weight gain. Women developing GDM were matched to three controls by self-reported prepregnancy body mass index (BMI), maternal age, race, and parity. Women without documented pregravid or 22- to 24-week weights and multiple gestations were excluded. The primary outcome was weight gain through 24 weeks of gestation.

Results: Six hundred fifty-two women (163 in the GDM group and 489 controls) underwent chart review. There were no significant differences in race (36% compared with 36% African American, P=.99), age (28.7 ± 6.3 years compared with 29.4 ± 6.9 years, P=.26) or prepregnancy BMI (31.7 ± 8.2 compared with 31.8 ± 8.6, P=.88). Maternal weight gain was higher in the GDM group than in the control group (14.8 compared with 11.2 lb, P<.001). When controlling for prepregnancy BMI, overweight (18.6 compared with 12.9 lb, P<.004), and obese (12.6 compared with 8.8 lb, P<.008), GDM participants gained significantly more weight by 24 weeks. Both diet-controlled (A1) and insulin-requiring (A2) GDM had higher weight gain compared with controls (control compared with A1: 11.2 compared with 15.3 lb, P=.029; control compared with A2: 11.2 compared with 14.6 lb, P=.018. No difference was found between A1 and A2 patients (P=.942).

Conclusion: Women who develop GDM have higher gestational weight gain through 24 weeks. Gestational weight gain is a significant risk factor for GDM in the overweight or obese patient but not in patients who were underweight or had a normal BMI before pregnancy.