Racial/Ethnic Disparities in Inadequate Gestational Weight Gain Differ by Pre-pregnancy Weight

OBJECTIVES: Pre-pregnancy body mass index (BMI) varies by race/ethnicity and modifies the association between gestational weight gain (GWG) and adverse pregnancy outcomes, which disproportionately affect racial/ethnic minorities. Yet studies investigating whether racial/ethnic disparities in GWG vary by pre-pregnancy BMI are inconsistent, and none studied nationally representative populations. METHODS: Using categorical measures of GWG adequacy based on Institute of Medicine recommendations, we investigated whether associations between race/ethnicity and GWG adequacy were modified by pre-pregnancy BMI [underweight (<18.5kg/m(2)), normal weight (18.5-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), or obese (≥30.0 kg/m(2)) ] among all births to Black, Hispanic, and White mothers in the 1979 USA National Longitudinal Survey of Youth cohort (n=6849 pregnancies; range=1-10). We used generalized estimating equations, adjusted for marital status, parity, smoking during pregnancy, gestational age, and multiple measures of socioeconomic position. RESULTS: Effect measure modification between race/ethnicity and pre-pregnancy BMI was significant for inadequate GWG (Wald test p-value=0.08). Normal weight Black (Risk Ratio (RR)=1.34, 95% confidence interval (CI): 1.18, 1.52) and Hispanic women (RR=1.33, 95%CI: 1.15, 1.54) and underweight Black women (RR=1.38; 95% CI: 1.07, 1.79) experienced an increased risk of inadequate GWG compared to Whites. Differences in risk of inadequate GWG between minority women, compared to White women, were not significant among overweight and obese women. Effect measure modification between race/ethnicity and pre-pregnancy BMI was not significant for excessive GWG. CONCLUSIONS: The magnitude of racial/ethnic disparities in inadequate GWG appears to vary by pre-pregnancy weight class, which should be considered when designing interventions to close racial/ethnic gaps in healthy GWG

Evidence for a Complex Relationship Among Weight Retention, Cortisol and Breastfeeding in Postpartum Women

OBJECTIVE: To assess the relationship between cortisol slope, a biologic marker of stress, and postpartum weight retention. METHODS: We included 696 women in a secondary analysis from a multi-site study conducted using principles of community-based participatory research to study multi-level sources of stress on pregnancy outcomes. As a stress marker, we included salivary cortisol slope; the rate of cortisol decline across the day. Pre-pregnancy weight and demographic data were obtained from the medical records. At 6 months postpartum, patients were weighed and returned saliva samples. We built stepwise regression models to assess the effect of demographic variables, cortisol slope and cortisol covariates (wake time, tobacco use and breastfeeding) on postpartum weight retention. RESULTS: 45.5 % of participants were African American, 29.2 % White, and 25.3 % Hispanic. Of the Hispanic women 62.5 % were Spanish speaking and 37.5 % were English speaking. In general, participants were young, multiparous, and overweight. Postpartum, almost half (47.6 %) of women studied retained >10 lbs. In multivariable analysis including age, pre-pregnancy BMI and public insurance, cortisol slope was significantly associated with weight retention (β = −1.90, 95 % CI = 0.22–3.58). However, when the model was adjusted for the cortisol covariates, breastfeeding (β = −0.63, 95 % CI = − 1.01 to −0.24) and public insurance (β = 0.62, 95 % CI = 0.20–1.04) were the two strongest correlates of weight retention. CONCLUSIONS FOR PRACTICE: The association between cortisol slope and postpartum weight retention appears to be influenced breastfeeding status