Endocrine Abstracts

Introduction: Nutritional therapy is essential in the treatment of gestational diabetes mellitus (GDM). International recommendations suggest a target of 5–9 kg weight gain in obese women during pregnancy. However, some studies advocate a reduced weight gain (<5 kg) due to better obstetric and neonatal outcomes, compared to an adequate or excessive weight gain.

Aim: To compare obstetric and neonatal outcomes of obese women with GDM with insufficient, adequate and excessive weight gain during pregnancy.

Methods: A cohort of 4563 women with GDM, single fetus pregnancy and pre-pregnancy BMI ≥ 30 kg/m² from the Portuguese Registry of GDM was analysed. T-test and Mann-Whitney U test were used to compare two groups for parametric and non-parametric variables, respectively. Chi square test was used to study differences between categorical variables. A level of significance α = 0.05 was noted.

Results: Women presented a mean age of 33.29 ± 5.26 years old and a median pre-pregnancy BMI of 34.86 (IQR 5.36) kg/m². GDM were diagnosed in median at 23 (IQR 16) weeks of pregnancy. From all, 34.5%, 30.4% and 35.2% had insufficient, adequate and excessive gestational weight gain. The newborn’s growth was evaluated according to Fenton curves in 98% of cases. Women with insufficient gain weight had a higher prevalence of small for gestational age (SGA), compared with the other two groups (13.1% vs 8.3% vs 7.5%, P < 0.0001). By multiple logistic regression, insufficient weight gain during pregnancy was found to increase the possibility of SGA by 76% (OR = 1.755, 95% CI = 1.436–2.145, P < 0.0001). A lower value of HbA1c in 3rd trimester was presented in pregnancies with insufficient weight gain (5.29 ± 0.60 vs 5.34 ± 0.45 vs 5.45 ± 0.52, OR = 0.612, 95% CI = 0.518–0.724, P < 0.001). Post-partum reclassification of diabetes was performed in 3123 women. Those with insufficient gestational weight gain had a higher prevalence of normal results), compared with the other two groups (91.4% vs 88.7% vs 88.5%, P = 0.004 and P = 0.002). No significant differences were found regarding week of diagnosis, treatment with insulin, gestational age, prematurity, global neonatal morbidity, neonatal hypoglycaemia or neonatal intensive care hospitalization between women with insufficient gain weight and the other two groups.

Conclusion: In clinical practice, we are very strict regarding weight gain in obese pregnant women, even those with insufficient weight gain. However, our data seems to validate the international recommendations because reduced weight gain could be harmful to the newborn growth.