Fluctuations in C-reactive protein concentration and neutrophil activation during normal human pregnancy

To clarify the changes in serum C-reactive protein (CRP) levels and in the neutrophil activation state during normal human pregnancy.

A longitudinal study (n=23) was performed during the three trimesters of pregnancy; a group of non-pregnant women (n=24) was used as control. Total and differential leukocyte count, serum concentration of CRP and plasma levels of granulocyte-macrophage colony stimulating factor (GM-CSF) and of lactoferrin and elastase (two indirect markers of neutrophil activation) were measured.

Pregnancy imposed an inflammatory response in the mother, observed by the significant increment in total white blood cell (WBC) and neutrophil counts and in the circulating levels of CRP, GM-CSF and lactoferrin, in all trimesters of gestation compared with non-pregnant controls. Plasma elastase concentration was also significantly higher in pregnant women, but only in the first trimester of gestation. Regarding the ratios of lactoferrin and elastase per neutrophil, they were significantly lower in pregnant women (all trimesters). During gestation, WBC and neutrophil count increased significantly from the first to the second trimester and remained high in the third period. In contrast, the ratios of lactoferrin and elastase per neutrophil decreased significantly from the first to the second trimester, remaining low in the last trimester. Concerning CRP levels, no consistent changes were observed throughout gestation; 12 cases (52.2%) presented fluctuations, whereas 7 (30.4%) showed progressive reductions and 4 (17.4%) progressive increments throughout pregnancy.

Changes in CRP levels vary in a wide manner between subjects along pregnancy, even though median values are consistently elevated throughout pregnancy. Moreover, circulating levels of neutrophil-activation products are higher in normal human gestation.