Nutritional status and factors associated with gestational weight gain in the city of São Paulo, 2012 to 2020: a retrospective cohort study.

Background: Gestational weight gain (GWG) is a critical issue related to postpartum health in newborns and mothers. In Brazil, pregnant women's public health recommends monitoring GWG. Therefore, the objective of this study is to evaluate gestational weight gain and associated health factors of pregnant women monitored at Unified Health System (SUS) in the city of São Paulo between 2012 and 2020.

Methods: This is a retrospective cohort study of pregnant women seen from 2012 to 2020 in São Paulo, Brazil. The database used was from the Integrated Health Care Management System related to the Live Birth Information System. Data distribution was assessed using the Kolmogorov-Smirnov test. Comparisons between groups according to weight gain (LWG vs. AWG vs. EWG) were performed using analysis of variance (ANOVA) with Tukey post hoc. Inclusion criteria considered that pregnant women had a recorded initial weight before 13 weeks and up to 15 days before delivery and a single pregnancy. The final database includes 276.220 pregnant women.

Results: The frequency of women according to initial body mass index (BMI) was 12.004 (4.4%) underweight, 132.049 (48.3%) normal weight, 78.856 (28.8%) overweight, and 50.660 (18.5%) living with obesity. The population consisted of 59.881 (21.9%), 37.217 (13.6%) and 176.471 (64.5%) women with LWG, AWG and EWG, respectively. Weight gain was associated with initial BMI, type of birth, color/ethnicity, marital status, women's age and antenatal care visits.

Conclusion: The proportion of pregnant women with inadequate weight gain is high, relating initial BMI, type of birth, color/ethnicity, marital status, women's age and antenatal care visits. Interventions such as nutritional education should be suggested to help achieve adequate GWG.