Importance: Postpartum weight retention increases lifetime risk of obesity and related morbidity. Few effective interventions exist for multicultural, low-income women.
Objective: To test whether an internet-based weight loss program in addition to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC program) for low-income postpartum women could produce greater weight loss than the WIC program alone over 12 months.
Design, setting, and participants: A 12-month, cluster randomized, assessor-blind, clinical trial enrolling 371 adult postpartum women at 12 clinics in WIC programs from the California central coast between July 2011 and May 2015 with data collection completed in May 2016.
Interventions: Clinics were randomized to the WIC program (standard care group) or the WIC program plus a 12-month primarily internet-based weight loss program (intervention group), including a website with weekly lessons, web diary, instructional videos, computerized feedback, text messages, and monthly face-to-face groups at the WIC clinics.
Main outcomes and measures: The primary outcome was weight change over 12 months, based on measurements at baseline, 6 months, and 12 months. Secondary outcomes included proportion returning to preconception weight and changes in physical activity and diet.
Results: Participants included 371 women (mean age, 28.1 years; Hispanic, 81.6%; mean weight above prepregnancy weight, 7.8 kg; mean months post partum, 5.2 months) randomized to the intervention group (n = 174) or standard care group (n = 197); 89.2% of participants completed the study. The intervention group produced greater mean 12-month weight loss compared with the standard care group (3.2 kg in the intervention group vs 0.9 kg in standard care group, P < .001; difference, 2.3 kg (95% CI, 1.1 to 3.5). More participants in the intervention group than the standard care group returned to preconception weight by 12 months (32.8% in the intervention group vs 18.6% in the standard care group, P < .001; difference, 14.2 percentage points [95% CI, 4.7 to 23.5]). The intervention group and standard care group did not significantly differ in 12-month changes in physical activity (mean [95% CI]: -7.8 min/d [-16.1 to 0.4] in the intervention group vs -7.2 min/d [-14.6 to 0.3] in the standard care group; difference, -0.7 min/d [95% CI, -42.0 to 10.6], P = .76), calorie intake (mean [95% CI]: -298 kcal/d [-423 to -174] in the intervention group vs -144 kcal/d [-257 to -32] in the standard care group; difference, -154 kcal/d [-325 to 17], P = .06), or incidences of injury (16 in the intervention group vs 16 in the standard care group) or low breastmilk supply from baseline to month 6 (21 of 61 participants in the intervention group vs 23 of 72 participants in the standard care group) and from month 6 to 12 (13 of 32 participants in the intervention group vs 14 of 37 participants in the standard care group).
Conclusions and relevance: Among low-income postpartum women, an internet-based weight loss program in addition to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC program) compared with the WIC program alone resulted in a statistically significant greater weight loss over 12 months. Further research is needed to determine program and cost-effectiveness as part of the WIC program.
Trial registration: clinicaltrials.gov Identifier: NCT01408147.