Weight gain during pregnancy and the probability of macrosomia in women with gestational diabetes.

Objective: To analyze the association between gestational weight gain in women with gestational diabetes and an increased risk of macrosomia.

Materials and methods: Cohort study with 139 pregnant women screened by a single-step oral glucose tolerance curve between 24-28 weeks of gestation were confirmed with gestational diabetes and sent to a hospital. Pre-pregnancy body mass index (BMI) was calculated from pre-pregnancy weight. Weight was measured at each prenatal consultation. The reference category was women with normal prenatal BMI who gained appropriate weight during pregnancy. At each visit, medical nutrition therapy (MNT) consisted of nutritional counseling, physical activity plan, and insulin therapy. Compliance with MNT was measured by capillary glucose measurements taken by each participant at home.

Results: 74.8% were primiparous, and 28.8% had normal pre-pregnancy BMI. The no linear logistic regression model showed women with normal pre-pregnancy BMI had twice (OR= 2.08, 95%CI: 1.07,4.05) the possibility of macrosomia, compared to mothers with overweight or obesity, adjusting for Capurro index, number of children in the family, and percent of compliance MNT. Macrosomia was the most prevalent childhood complication (12.3%).

Conclusion: Women with normal pre-pregnancy BMI who gained more weight during pregnancy were at higher risk of having macrosomic infants.