Postpartum Metabolic Health: Social Determinants of Health, Weight Retention, and Predictors of LDL-C in Women with Recent Gestational Diabetes Mellitus (GDM)

Abstract

Paper 1: Title: Association of Social Determinants of Health Measured by Social Vulnerability Index (SVI) With Postpartum Weight Retention among Women with Recent Gestational Diabetes Mellitus Authors: Moomtahina Fatima, MBBS 1,4; Jacinda Nicklas, MD, MPH 2; Geetha Iyer, MBBS, MD, MPH, PHD 3; Ellen W Seely, MD 1,4 Affiliation: 1Harvard Medical School ; 4Division of Endocrinology, Brigham and Women's Hospital, Boston, USA ; 3University of Colorado Medical Center, Aurora, CO, USA ; 4Harvard Pilgrim Health Care Institute Abstract Background and Objective: In women with a history of gestational diabetes mellitus (GDM), postpartum weight retention (PPWR) increases the risk of type 2 diabetes mellitus (T2DM). The association between social determinants of health (SDoH) and PPWR in women with recent GDM remains unclear. We examined the relationship between the Social Vulnerability Index (SVI), a composite measure of community-level disadvantage, and PPWR among women with recent GDM. Additionally, we explored the association between individual components of SVI and PPWR to assess the relative contributions of specific domains of social vulnerability. Methods: This secondary analysis of the Balance After Baby Intervention (BABI) trial (2016–2019) used county-level SVI scores from the CDC’s 2020 database, categorized into tertiles (low, moderate, high vulnerability). PPWR at 12 months postpartum was calculated as the difference between pre-pregnancy and postpartum weight. Multivariable linear regression models evaluated the association between SVI tertiles and PPWR, adjusting for key confounders. Results: Among 142 participants, women in the second tertile (moderate SVI) had significantly higher PPWR at 12 months postpartum than those in the lowest tertile (adjusted mean difference: 6.71 lbs, 95% CI: 2.07–11.35, p = 0.007), while PPWR was not significantly different for the third tertile. The socioeconomic and racial/ethnic minority status domains of SVI were positively associated with PPWR, while the housing and transportation domain was negatively associated. Conclusions: Moderate social vulnerability is associated with increased PPWR in women with prior GDM. These findings highlight the need for targeted interventions in moderately vulnerable populations to reduce PPWR, thereby mitigating risk of T2DM. Keywords: postpartum weight retention, gestational diabetes mellitus, social vulnerability index, social determinants of health. Paper 2: Title: Six-Week Postpartum Predictors of LDL-C Levels at One Year Postpartum in Women with Recent Gestational Diabetes Mellitus Authors: Moomtahina Fatima, MBBS 1,5; Emily C Tan, BS 2; Christine E Horn, BA 3; Jacinda Nicklas, MD, MPH 4 ; Ellen W Seely, MD 1,5 Affiliation: 1Harvard Medical School ; 5Division of Endocrinology, Brigham and Women's Hospital, Boston, USA ; 2Memorial Sloan Kettering Cancer Center; 3Larner College of Medicine, University of Vermont; 4University of Colorado Medical Center, Aurora, CO, USA. Abstract Background: Women with prior gestational diabetes mellitus (GDM) are at an increased risk of developing type 2 diabetes (T2DM). During pregnancy, they exhibit higher levels of LDL, triglycerides (TG), and total cholesterol (TC), and lower HDL levels than those without GDM. However, the postpartum (PP) trajectory of LDL-C remains unclear. Identifying early postpartum predictors of LDL-C at 12 months could help target high-risk women for timely follow-up and intervention to reduce long-term cardiometabolic risk. Objective: This study aims to identify predictors of LDL-C levels at 12 months PP in women with recent GDM based on clinical measures at six weeks PP, using the best-fitting backward stepwise multivariable linear regression analysis. A secondary objective was to assess whether change in PP weight, continued systemic hormonal contraceptive use, and breastfeeding from six weeks to 12 months PP improved model fit. Methods: This was a secondary analysis of the Balance After Baby Intervention (BABI) trial, a web-based lifestyle intervention conducted between 2016 and 2019 across three U.S. clinical sites among women with GDM in their most recent pregnancy. Results: The final analytic sample comprised 122 women. The mean age at screening was 33 ± 5 years. The cohort was racially and ethnically diverse: 33% Hispanic, 49% White, 19% Black/African American, 19% Asian, and 13% other races/ethnicities. Regarding socioeconomic status, 55% were college graduates, and 81% had an annual household income ≥ $35,000. Stepwise backward multivariable linear regression analysis revealed LDL-C at six weeks postpartum (β = 0.66, 95% CI: 0.57–0.76, p 0.001) and breastfeeding at six weeks postpartum (β = -9.13, 95% CI: -17.34, -0.93, p = 0.029) were significant predictors of LDL-C levels at 12 months postpartum. In an extended model incorporating weight change from six weeks to 12 months postpartum, continued systemic hormonal contraceptive use (β = 14.67, 95% CI: 3.26–26.08, p = 0.012) and maternal age (β = 0.82, 95% CI: 0.05–1.60, p = 0.036) were also significantly associated with LDL-C levels at 12 months. The final model (Model 4) demonstrated improved fit (Adjusted R² = 0.633, AIC = 884.318). Conclusion: LDL-C levels at six weeks postpartum is a significantly predictor of LDL-C levels at 12 months in women with recent GDM. Early postpartum breastfeeding appears protective against elevated LDL-C, whereas continued systemic hormonal contraceptive use is associated with higher LDL-C levels. Additionally, older maternal age was linked to higher LDL-C at 12 months postpartum. Given that the ADA and ACOG recommend an OGTT at 4–12 weeks postpartum for women with GDM, this routine visit presents a potential opportunity to concurrently perform lipid screening. Identifying women at risk of elevated LDL-C at 12 months postpartum through early postpartum lipid screening enables the implementation of targeted interventions aimed at reducing long-term cardiovascular risk. Keywords: Gestational diabetes mellitus, postpartum dyslipidemia, LDL cholesterol, breastfeeding, hormonal contraception, cardiovascular risk