Immunology of Pregnancy and Systemic Consequences

The uterus is a site rich in immune cells and is subject to regulation by the sex hormones progesterone and estrogens. Immune modulation within the uterus is initiated during coitus and continues through to the delivery of the baby and for some time postpartum. Several mechanisms to protect the semiallogeneic fetus from maternal immune attack exist, with the carefully regulated recruitment and function of immune cells, as well as the mediators they produce, now recognized as crucial to the success of pregnancy. In the postpartum period, immune cells are also vital to aid the repair and remodeling process, as well as ensure defense against pathogens. Dysregulation of these maternal immune mechanisms can lead to the development of conditions such as preeclampsia, preterm birth, and spontaneous abortion. This chapter will evaluate the immune environment within the uterus and the systemic consequences from coitus to postpartum uterine involution. The effect of pregnancy-associated immune modulation on the symptoms of the autoimmune diseases such as arthritis and systemic lupus erythematosus (SLE) pregnancy-associated infections is also reviewed.