Objective: To identify gestational weight gain trajectories and their association with demographic, obstetric, and anthropometric characteristics.
Method: Information of 599 pregnant women undergoing prenatal care in public health units was collected through questionnaires and medical records, resulting in 4,272 measures of body weight. Group-based trajectory models were applied to identify patterns of gestational weight gain.
Results: The average gestational weight gain at 40 weeks was 14.1 kg (95%CI: 13.2, 15.0). Three different trajectory groups were identified: low (9.9%), intermediate (66.4%), and high (23.7%). Pregnant women who smoked and those classified above IOM's weight gain recommendations were more likely to be classified in the group with a high weight gain trajectory; while those with pre-pregnancy overweight or obesity, and with greater parity were more likely to be categorized in the low weight gain trajectory. After adjusting for other variables in the model, parity remained significantly associated with gestational weight gain (β: 0.88; 95%CI: 0.27, 0.73). In the multilevel model, weight gain remained different among the categories of group-based trajectory, even after adjustment for other investigated variables for intermediate (β: 2.94; 95%CI: 2.32, 3.58) and high (β: 5.88; 95%CI: 5.09, 6.66) gestational weight gain trajectory groups.
Conclusions: Behavioral, obstetric, and anthropometric characteristics determined the belonging to groups with a high or low trajectory of gestational weight gain. The findings contribute to a better understanding of patterns of gestational weight gain in middle-income women groups.
Keywords: Weight gain; group-based trajectory; longitudinal studies; multilevel analysis; obesity; overweight; pregnancy.