Postpartum Weight Trajectories In A Cohort Of 127 Samoan Women: Does Breastfeeding Protect Against Postpartum Weight Retention?

Grace Castillo

This thesis is restricted to Yale network users only. It will be made publicly available on 08/28/2020


Rising global obesity rates impact every aspect of health, including maternal-fetal health. Samoa has a disproportionate burden of obesity, with more than half of Samoan women entering pregnancy obese. Given Samoan women’s high parity (4), postpartum weight retention (PPWR) may be a significant source of weight gain over women’s lifetimes. Little is currently known about PPWR among Samoan women, so this analysis sought to document PPWR trajectories, assess factors – like breastfeeding -- associated with PPWR. Data of 127 mother-infant dyads from the 2017 Foafoaga O le Ola cohort were used in analysis. Researchers collected demographic and lifestyle data, as well as height measures. Maternal postpartum weight was collected at Visit 1 (1 week), Visit 2 (2 months), and Visit 3 (4 months). We a mixed method approach (“PROC MIXED”) with an unspecified covariance structure (“Type=un”) to evaluate PPWR and breastfeeding’s impact. The ‘lsmeans’ statement was used to generate least squares means and to compare means across different levels of the predictor variables. Women had an average age of 26.9 years, an average Visit 1 BMI of 34.1, and an average parity of 1.87. The final model included maternal education (F(2,116)=3.47, p=0.03), time (F(2,116)=13.3, p=<0.001), age (F(2,116)=3.63, p=0.03), and breastfeeding F(2,116)=0.24, p=0.79). We included breastfeeding in the final model since it was a predictor of interest, but it was not significant. The least squares means found greater age and maternal education indicated higher predicted BMI. 33.9 percent of the sample gained weight by Visit 3. PPWR may be a significant source of continued weight gain for this population, and breastfeeding does not mitigate the risk of PPWR. More attention is needed in the postpartum period. Future research should focus on mitigating PPWR and characterizing its relation to gestational weight gain. Key words: Postpartum weight retention, maternal health, breastfeeding, Samoa, obesity, chronic disease epidemiology