Adverse Perinatal Outcomes and Postpartum Multi-Systemic Dysregulation: Adding Vitamin D Deficiency to the Allostatic Load Index

Background Allostatic load (AL) is an index of multi-system physiological "wear-and-tear," operationalizing emergent chronic disease risk and predicting morbidity and mortality. AL has been proposed as an organizing framework for studying pregnancy outcomes and additional AL biomarkers for the study of maternal health would be valuable. Objectives To test whether adverse perinatal outcomes are associated with postpartum AL and if including vitamin D deficiency (serum 25(OH)D < 20 ng/ml) as an additional marker of postpartum AL increases the association. Methods The Community Child Health Network is a community-based participatory research network that enrolled women at birth and followed them for 2 years measuring ten biomarkers (body mass index, waist: hip ratio, pulse, systolic and diastolic blood pressures, cortisol slope, c-reactive protein, hgbA1c, HDL, and total cholesterol) at 6 and 12 months postpartum. A composite of four adverse perinatal outcomes (low birth weight, preterm birth, preeclampsia, and gestational diabetes) was collected from medical charts in a sample of 164 women from one site and serum 25(OH)D status was measured 24-39 weeks postpartum in this cohort. Results Twenty-nine percent experienced one or more of the four adverse perinatal outcomes. Serum 25(OH)D was significantly inversely correlated with the AL index (Spearman's r = -0.247, p = 0.002). Logistic regression results adjusting for maternal age and race showed that adverse outcome was significantly associated with higher postpartum AL (OR 1.53 for a 1-unit increase in AL, 95% CI 1.24-1.89). Adding 25(OH)D deficiency as an 11th component to the AL index improved the model fit (Delta (-2LogL) = 3.955, p = 0.047), and improved the Akaike information criterion (180.32 vs. 184.27). Conclusion Women with adverse perinatal outcomes have higher postpartum AL and adding vitamin D deficiency to the AL index strengthens this association.