Introduction: To evaluate the effect of a culturally-modified, motivationally-targeted, individually-tailored lifestyle intervention on postpartum weight retention among Hispanic women with overweight/obesity.

Materials and methods: Proyecto Mamá was a randomized controlled trial conducted in western Massachusetts (2014-2020). Hispanic women with overweight/obese pre-pregnancy BMI (n = 148) were randomized in early pregnancy to a Lifestyle Intervention (LI) or a Health & Wellness (HW) comparison arm. The LI was based upon theoretical concepts, used a low-cost, high-reach strategy, and focused on healthy exercise and diet with follow-up through 12-months postpartum. The primary outcome of change in weight was calculated as the difference between pre-pregnancy weight and 6-week, 6-month, and 12-month postpartum weight. The secondary outcome was achievement of 5 % weight reduction from pre-pregnancy weight. Retention was 68.2 % in the overall postpartum period and 31.0 % at 12-months.

Results: In intent-to-treat analyses, compared to the HW arm, there was no difference in postpartum weight retention at 6-weeks (0.0 kg, 95 % CI: -3.4, 3.5), 6-months (-1.8 kg, 95 % CI: -5.6, 2.0), or 12-months (-2.0 kg, 95 % CI: -7.0, 3.1). In a secondary complete case analysis, compared to the HW arm, the LI arm had 5.5 times higher odds of meeting the postpartum weight reduction goal (aOR = 5.5, 95 % CI: 1.7, 17.9) adjusting for pre-pregnancy weight.

Conclusions: A lifestyle intervention among at-risk Hispanic women with overweight/obesity had no overall impact on postpartum weight, but a beneficial impact among those who completed the trial. Future studies should focus on increasing the feasibility and acceptability of the intervention in this at-risk population.