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Pregnancy and immune stimulation: re‐imagining the fetus as parasite to understand age‐related immune system changes in US women
Author(s) -
Rivara Anna C.,
Miller Elizabeth M.
Publication year - 2017
Publication title -
american journal of human biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.559
H-Index - 81
eISSN - 1520-6300
pISSN - 1042-0533
DOI - 10.1002/ajhb.23041
Subject(s) - pregnancy , immune system , immunoglobulin e , immunology , population , biology , gestation , fetus , medicine , physiology , antibody , environmental health , genetics
Objectives Pregnancy can increase production of Immunoglobulin E (IgE), an immune response more often directed towards parasite infections. An absence of parasitism makes the US population ideal to test the hypothesis that the maternal immune system recognizes a fetus as a parasite. We predict that total IgE levels are positively associated with a history of pregnancy across all ages of adult women, mirroring patterns of IgE in parasitized populations. Methods Reproductive‐aged women ( n = 2201) from the National Health and Nutrition Examination Survey 2005‐2006 were analyzed in a cross‐sectional design using complex survey regression and multiple imputation to evaluate associations between total IgE levels, pregnancy history, and interactions between age and pregnancy. Results Women with a history of pregnancy have significantly higher IgE levels and a significantly shallower slope of IgE levels across ages ( P = .031). Conclusions This research supports the hypothesis that maternal immune systems respond to prior pregnancies as they do to macro‐parasitic exposures, and may modify the expected linear declines of IgE levels in women that accompanies aging. These finding have implications for understanding the evolution of internal gestation in mammals.