Endocrine Abstracts

Introduction: Gestational diabetes mellitus (GDM) is a risk factor for large for gestational age (LGA) newborns. The optimization of glycemic control and weight gain restriction during pregnancy according to BMI has contributed to decrease LGA but may increase the risk of small for gestational age (SGA).

Aim: To evaluate the predictors of SGA in women with DGM.

Methods: A cohort of 5271 Portuguese women from the National Registry of GDM was studied. Demographic, anthropometric and analytical data and maternal-fetal outcomes were evaluated.

Results: Women presented a mean age of 33.14±5.4 years, mean BMI of 26.99±5.81 kg/m² and mean weight gain during pregnancy of 9.63±5.78 kg. The newborn’s growth was evaluated according to Fenton curves in 4727 cases. We identified 3898 (82.5%) newborns appropriate for gestational age (AGA), 180 (3.8%) LGA and 649 (13.7%) SGA. Women with SGA had a significant lower pre-pregnancy weight (66.95±15.20 vs 71.01±16.04, P<0.001) and BMI (26.07±5.75 vs 27.06±5.77; P<0.001). The prevalence of SGA was lower in women with previous GDM (OR=0.592, 95%CI=0.466–0.805, P<0.001) or macrosomia (OR=0.274, 95%CI=0.145–0.520, P<0.001) and greater number of pregnancies (OR=0.798, 95%CI=0.737–0.863, P<0.001) and two-fold higher in twin pregnancies (OR=2.059, 95%CI=1.313–3.229, P=0.001). Insufficient weight gain during pregnancy increased the possibility of SGA by 35% (OR=1.346, 95%CI=1.127–1.609, P<0.001). A lower value of HbA1c in 3rd trimester was presented in pregnancies with SGA (5.18±0.38 vs 5.25±0.44, OR=0.662, 95%CI=0.516–0.849, P=0.001). No significant differences were found regarding age, week of diagnosis and treatment with insulin or oral antidiabetic agents.

Conclusion: In our sample, the prevalence of SGA was 3.5 times higher compared to LGA. Women without previous GDM or macrosomia, with lower BMI before pregnancy, insufficient weight gain during pregnancy, lower HbA1c in 3rd trimester and twin pregnancies had significantly more SGA. Monitoring fetal intrauterine growth, assessing risk-benefits of therapeutic and an individualized approach is required.