Benefit of insufficient gestational weight gain in obese women with gestational diabetes mellitus: A multicenter study in Portugal.

BACKGROUND: Both obesity and gestational diabetes mellitus (GDM) are independent risk factors for adverse maternal and fetal outcomes. The Institute of Medicine (IOM) recommends different targets for an adequate gestational weight gain (GWG), depending on the prepregnancy body mass index, but they have been questioned. We aim to compare obese pregnant women with GDM according to GWG stratification (insufficient, adequate and excessive) with regard to maternal and neonatal outcomes and to clarify whether insufficient GWG can be associated with better outcomes. METHODS: A multicenter observational study with prospectively collected data of obese singleton pregnant women with GDM was conducted. GWG was expressed according to the 2009 IOM's recommendations. RESULTS: Of 4563 obese women with GDM, 34.5%, 30.4% and 35.2% registered insufficient, adequate and excessive GWG, respectively. Multiple logistic regression analysis revealed that women with insufficient GWG had lower odds of gestational hypertension, preeclampsia, caesarean section, large for gestational age (LGA) neonates and prediabetes in postpartum. Despite the higher incidence of small for gestational age (SGA) neonates, they were not associated with adverse outcomes. Women with excessive GWG had higher odds of caesarean section, macrosomic and LGA neonates. CONCLUSIONS: Insufficient GWG in obese women with GDM was beneficial due to better maternal and neonatal outcomes. In clinical practice, we should be strict with regard to weight gain in obese pregnant women with GDM and encourage a reduced GWG, provided an adequate fetal growth is guaranteed.