Gestational weight gain and adverse maternal outcomes in Brazilian women according to body mass index categories: An analysis of data from the Birth in Brazil survey.

Background & Aims: Monitoring gestational weight gain (GWG) is relevant for perinatal outcomes, especially in the context of increasing obesity and overweight in the female population. This study analyses the association between GWG in Brazilian women, according to different body mass index (BMI) categories, and different outcomes, including hypertensive disorders of pregnancy (HDP), gestational diabetes (GD) and caesarean section.

Methods: Data on women from all the major regions of Brazil with a single pregnancy of a gestational age of 28 weeks or more and information available for anthropometric evaluation were included in the Birth in Brazil survey. Adequacy of GWG was assessed according to the percentile distribution of GWG of women with favourable neonatal outcomes, with the median of the distribution referred to as 100% adequacy in the GWG evaluation.

Results: The study consisted of 18,953 women, 58.3% of whom were normal weight and 35.1% were overweight. The adequacy of GWG was better amongst the normal weight women (91.1%) and worse amongst those with class III obesity (46.0% with excessive GWG), with the latter showing the highest occurrence of adverse outcomes. Results of the multivariate logistic regression analysis revealed that weight gain above 200% of the median in the normal weight, overweight and obese women was positively associated with HDP and caesarean section, but not with GD.

Conclusions: The proposed ranges of appropriate GWG associated with favourable neonatal outcomes based on the data from the Birth in Brazil survey proved good predictors of HDP and caesarean section amongst the women included in the study.