Changes in serum immunity during pregnancy.

Pregnancy requires a host of localized immune factors that allow the mother to tolerate the fetus. Changes in the mother's serum immunity during pregnancy are less well-known. To clarify these changes, 1,351 women from the NHANES 1999-2000 were analyzed with complex survey regression to test the effect of pregnancy on adaptive and innate immune markers. Adjusting for age and BMI, pregnant women had higher C-reactive protein levels and white blood cell counts and lower measles antibody titer and lymphocyte counts than nonpregnant women. This dual pattern of immunological changes supports the hypothesis that mothers will reduce the ability of the adaptive immune system to respond to infection while increasing the activity of innate immunity during pregnancy, maintaining immune function homeostasis. The function of these homeostatic immune responses is unknown. (c) 2009 Wiley-Liss, Inc.