Background: Traditional risk factors such as hyperlipidemia induce a state of inflammation that impairs vascular function. Despite marked maternal hyperlipidemia, endothelial function improves during pregnancy. In non-pregnant state increased circulating levels of pro-inflammatory cytokines and high sensitive C-reactive protein (hsCRP) lead to attenuated flow mediated vasodilation. Relation between endothelial function and pro-inflammatory cytokines has not been studied thoroughly in pregnancy. The aim of this study was to evaluate the effect of pregnancy on hsCRP and pro-inflammatory cytokines and their associations with vascular endothelial function.
Methods: As part of population-based, prospective cohort Cardiovascular Risk in Young Finns study conducted in Finland we measured brachial artery flow mediated dilation (FMD) and serum concentrations of hsCRP, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in 57 pregnant Finnish women throughout gestation and 62 control women matched for age and smoking.
Results: HsCRP-concentration was greater in pregnancy compared to non-pregnant controls (median hsCRP 2.52 mg l(-1) versus 1.21 mg l(-1), P<0.001). IL-6-concentration was slightly increased in pregnancy compared with the non-pregnant controls (median 1.66 versus 1.32 mg l(-1), non-significant [NS]) and TNF-alpha-concentration was slightly decreased in pregnant group (2.11 versus 2.38 pg ml(-1), NS). FMD increased during pregnancy and IL-6 had a positive correlation to the FMD in pregnancy (R = 0.288, P = 0.031).
Conclusions: Improvement of FMD in normal pregnancy was not affected by increase in hsCRP concentration. We found an association with IL-6 and FMD but we believe that improvement in endothelial function during normal pregnancy is not caused by variation in hsCRP, IL-6 or TNF-alpha.