Adiposity-related inflammation: effects of pregnancy

In the nonpregnant population, there is extensive evidence of a systemic low-grade inflammatory status in relation to excess adipose tissue. Less is known about the relation during pregnancy.

Our main objective was therefore to explore the effect of pregnancy on adiposity-related systemic inflammation.

This study is a longitudinal cohort study of 240 pregnant women of Scandinavian heritage at Oslo University hospital-Rikshospitalet, Norway from 2002 to 2005. The inflammatory markers (C-reactive protein [CRP], Interleukin-6 [IL-6], monocyte chemoattractant protein 1 [MCP-1], IL1-Ra, tumor necrosis factor receptor II, and IL-10) were measured at four timepoints during pregnancy and analyzed by enzyme immuno-assay. The women were categorized based on BMI at inclusion (BMI <25, 25-30, and >30 kg/m(2)). Data were analyzed by Friedman-test, Wilcoxon signed rank test, or Kruskal-Wallis test as appropriate.

Maternal adiposity was associated with significantly higher circulatory levels of several inflammatory markers (CRP, MCP-1, IL-6, and IL-1Ra). However, this proinflammatory upregulation was not evident toward the end of pregnancy, as levels of CRP, MCP-1, and IL-6 were not any longer significantly different between the BMI categories.

Although normal pregnancy exhibits proinflammatory features, this does not seem to have additive or synergistic effects on the inflammation associated with adiposity. On the contrary, we found that the BMI-dependent increase in proinflammatory markers was not evident at the end of pregnancy.