Comparison of two methods for assessing weight gain in Brazilian pregnant women

To compare two methods for assessing gestational weight gain (GWG) among overweight adult pregnant women receiving care in Primary Health Care.

This is a secondary analysis of a randomized controlled clinical trial conducted between 2018 and 2021 involving 260 overweight pregnant women receiving prenatal care at primary health care centers in the municipality of Ribeirão Preto, São Paulo. Participants were assigned to two groups: intervention (received individualized nutritional counseling- GI) or control (received only standard prenatal nutritional guidance-GC). Prenatal weight gain (PWG) was classified according to the U.S. guidelines of the National Academy of Medicine (NAM) and in accordance with Brazilian growth curve recommendations. To assess agreement between the methods, the kappa coefficient was used, and for the classification of weight gain (adequate, insufficient, or excessive), the criteria adopted by each method were used. Logistic regression models were employed to analyze the association between the groups (IG and GC) and the two methods used in the assessment of PWG.

Moderate agreement was observed between the methods, with a pattern of disagreement indicating possible underestimation of GPG by the NAM guidelines. Pregnant women in the GI had a higher likelihood of insufficient GPG according to the Brazilian method (OR = 2.87; 95%CI 0.88-9.25) and a lower likelihood of excessive weight gain according to the US method (OR = 0.63; 95%CI 0.34-1.17), compared to women in the GC, although neither finding was statistically significant.

The Brazilian curves proved to be more appropriate for classifying GPG in overweight Brazilian pregnant women, better reflecting weight monitoring during prenatal care. Their adoption may facilitate the early identification of GPG inadequacies and, consequently, contribute to improving the quality of prenatal care.