Implication of gestational diabetes treatment on maternal weight gain and low neonatal weight: a large retrospective cohort study

Objective: the treatment for gestational diabetes is based on diet, and this may modify maternal weight gain. The limited maternal weight gain is related to newborns with small weight for their gestational age (SGA), and many studies have found an increase of SGA in women with gestational diabetes (GD), but the reason for this is not clear. The objective of this study is to evaluate the effects of gestational diabetes treatment on maternal weight gain and neonatal weight. Methods: a retrospective cohort study of 1,765 patients with GD, according to the National Diabetes Data Group (NDDG) criteria. We assessed: pre-pregnancy BMI, total maternal weight gain (MWG), weight gain during the third trimester, gestational week of starting the treatment, and treatment modality (diet or diet plus insulin). Birth weight was adjusted by gestational age and gender: SGA (<= 10th) and large for gestational age (LGA) (> 90th). Results: the percentage of newborns with weight percentile <= 10 was 14.8%. The diet and the time of initiation of the treatment were related to maternal weight gain (MWG) in the third trimester. For every 1 kcal/kg of variation in the diet (increase or decrease), a MWG variation of 0.03 (0.001-0.06) kg occurred (p < 0.01). For each week before the beginning of treatment, the mother did not gain 0.13 +/- [(-0.15) - (-0.11)] kg in the third trimester (p < 0.01). The SGA was related to the lowest MWG in total gestation: 7.0 (IQR 3.0-10.4) kg vs. 8.4 (IQR 5.0-11.6) kg (p < 0.01), and in the third trimester: 0.3 (IQR -0.9-1.5) kg vs. 0.9 (IQR -0.3-2.2) kg (p < 0.01). Conclusion: the dietary treatment for gestational diabetes leads to a lower maternal weight gain and induces an impact on neonatal weight.