1132: Association of interleukin-6 and obesity across pregnancy

Abstract

There is evidence that obesity is associated with a state of chronic inflammation. Interleukin-6 (IL-6) is an inflammatory mediator that has been linked to adverse pregnancy outcomes. IL-6 levels are elevated in non-pregnant obese individuals. The association between IL-6 and obesity in pregnancy has not been well established. The objective of this study was to evaluate the association between obesity and IL-6 in pregnancy across gestation. A prospective cohort study of 744 pregnant women was conducted from 2013-2015 at four US sites. Participants were ≥ 18 years old with a singleton pregnancy, English speaking without fetal anomalies or steroid use. Women with recent infection, fever, or antibiotic treatment were excluded. Participants had two blood draws during pregnancy, first between 12w0d-20w6d gestation and second between 32w0d-35w6d gestation. Pre-pregnancy body mass index (BMI) was obtained by self-report. Linear regression was used to model associations between BMI category and percent change in serum IL-6 across study visits. Models were adjusted for maternal age, parity, race, education, time between study visits, gestational age at first study visit, smoking, and study site. Among the 744 participants, 72.8% (n=545) completed both blood draws and had complete covariate information. The mean log-transformed IL-6 levels at the initial study visit were 0.16±0.08, 0.20±0.08, and 0.25±0.09 among normal weight, overweight, and obese subjects, respectively (p< 0.01). IL-6 levels generally increased across gestation in all weight categories, however obese and overweight women had a significantly lower percent change across gestation (Table 1, Figure 1). IL-6 levels are elevated in obese and overweight pregnant women compared to their normal weight counterparts. However, across gestation women with normal pre-pregnancy BMIs experience greater percent change in IL-6 levels. Future work should evaluate how change in inflammation across pregnancy mediates the relationship between obesity and adverse outcomes.View Large Image Figure ViewerDownload Hi-res image Download (PPT)