Impact of gestational weight gain on obstetric and neonatal outcomes in obese diabetic women

Background: Both obesity and gestational diabetes mellitus are increasing in prevalence, being a major health problem in pregnancy with independent and additive impact on obstetrics outcomes. It is recognized that inadequate gestational weight gain is an independent risk factor for pregnancy-related morbidity. The aim of this study was to evaluate the effect of gestational weight gain on obstetric and neonatal outcomes in obese women with gestational diabetes. Methods: Retrospective multicenter study of obese women with gestational diabetes. The assessed group was divided into three categories: women who gained below (<5 kg), within (5-9 kg) and above (>9 kg) the 2009 Institute of Medicine recommendations. Maternal and neonatal outcomes were compared and adjusted odds ratios calculated controlling for confounders. Results: Only 35,1 % of obese women with gestational diabetes (n = 634) achieved the recommended gestational weight gain; 27,8 % (n = 502) gained below and 37,1 % (n = 670) above the recommendations. There was a positive correlation between gestational weight gain and neonatal birthweight (r = 0,225; p < 0,001). Gestational weight gain below recommendations was associated with lower odds for cesarean section, even adjusting for birthweight [aOR = 0,67 (0,54-0,85); p < 0,001]; lower odds for large for gestational age neonates [aOR = 0,39 (0,28-0,57); p < 0,001] and macrosomia [aOR = 0,34 (0,21-0,55); p < 0,001]. Excessive weight gain, even adjusting for birthweight, was associated with higher odds for cesarean section [aOR = 1,31 (1,07-1,61); p = 0,009], low Apgar score [aOR = 4,79 (1,19-19,21); p = 0,027], large for gestational age neonates [aOR = 2,32 (1,76-3,04); p < 0,001] and macrosomia [aOR = 2,39 (1,68-3,38); p < 0,001]. Conclusions: In obese women with gestational diabetes, a reduced gestational weight gain (< 5 kg) is associated with better obstetric and neonatal outcomes than an excessive or even an adequate weight gain. Therefore, specific recommendations should be created since gestational weight gain could be a modifiable risk factor for adverse obstetric outcomes.