Objective: To identify associations between second-trimester serum inflammatory biomarkers and preterm birth among obese women.
Methods: In this nested case-control study, we compared 65 serum inflammatory biomarkers in obese women whose pregnancies resulted in early spontaneous preterm birth (<32 weeks gestation, n = 34) to obese women whose pregnancies resulted in term birth (n = 34). These women were selected from a larger population-based California cohort. Random forest and classification and regression tree techniques were employed to identify biomarkers of importance, and adjusted odds ratios (aORs) and 95% confidence intervals (CI) were estimated using logistic regression.
Results: Random forest and classification and regression tree techniques found that soluble vascular endothelial growth factor receptor-3 (sVEGFR3), soluble interleukin-2 receptor alpha-chain (sIL-2RA) and soluble tumor necrosis factor receptor-1 (sTNFR1) were related to preterm birth. Using multivariable logistic regression to compare preterm cases and term controls, decreased serum levels of sVEGFR3 and increased serum levels of sIL-2RA and sTNFR1 were associated with increased risk of preterm birth among obese women, aOR = 3.2 (95% CI: 1.0-9.9), aOR = 2.8 (95% CI: 0.9-9.0), and aOR = 4.1 (95% CI: 1.2-14.1), respectively.
Conclusions: In this pilot study, we identified three serum biomarkers indicative of inflammation to be associated with spontaneous preterm birth among obese women: sVEGFR3, sIL-2RA and sTNFR1.
Keywords: Inflammation; inflammatory markers; obesity; preterm birth; soluble interleukin-2 receptor alpha-chain; soluble tumor necrosis factor receptor-1; vascular endothelial growth factor; vascular endothelial growth factor receptor-3.