Gestational diabetes and pre-pregnancy overweight: Possible factors involved in newborn macrosomia

摘要

Aim: Good glycemic control in gestational diabetes mellitus (GDM) seems not to be enough to prevent macrosomia (large-for-gestational-age newborns). In GDM pregnancies we studied the effects of glycemic control (as glycosylated hemoglobin [HbA1c]), pre-pregnancy body mass index (PP-BMI) and gestational weight gain per week (GWG-W) on the frequency of macrosomia. Methods: We studied 251 GDM pregnancies, divided into two groups: PP-BMI 25.0 kg/m 2 (the nonoverweight group; n = 125), and PP-BMI ≥ 25.0 kg/m 2 (the overweight group; n = 126). A newborn weight Z-score 1.28 was considered large-for-gestational-age. Statistical analysis was carried out using the Student's t-test and χ 2-test, receiver-operator characteristic curves and linear and binary logistic regressions. Results: Prevalence of macrosomia was 14.9% among GDM (n = 202/251, 88.4%) with good glycemic control (mean HbA1c 6.0%), and 28.1% in those with mean HbA1c ≥ 6.0% (n = 49/251, P 0.025). Macrosomia rates were 10.4% in the non-overweight group and 24.6% in the overweight group (P = 0.00308), notwithstanding both having similar mean HbA1c (5.48 ± 0.065 and 5.65 ± 0.079%, P = 0.269), and similar GWG-W (0.292 ± 0.017 and 0.240 ± 0.021 kg/week, P = 0.077). Binary logistic regressions showed that PP-BMI (P = 0.012) and mean HbA1c (P = 0.048), but not GWG-W (P = 0.477), explained macrosomia. Conclusions: Good glycemic control in GDM patients was not enough to reduce macrosomia to acceptable limits (10% of newborns). PP-BMI and mean HbA1c (but not GWG-W) were significant predictors of macrosomia. Thus, without ceasing in our efforts to improve glycemic control during GDM pregnancies, patients with overweight/obesity need to be treated prior to becoming pregnant.