Pregnancy and Susceptibility to Parasites

Successful pregnancy is dependent on many dynamic immunological events that occur at the maternal–fetal interface. While the trophoblast initiates implantation through the uterine wall, maternal immune mechanisms limit the extent to which the decidua is invaded by the placenta without disrupting pregnancy. Immunological reactions are not observed at the maternal–fetal interface. Pregnancy-induced modulation of systemic maternal immunity results in amelioration of certain autoimmune diseases and exacerbation of some infectious diseases. Alteration of immunological function during pregnancy in some circumstances might facilitate congenital transmission of certain pathogens. In other circumstances, the immune reactions induced by pathogens might result in disruption of pregnancy. These complex interactions are discussed in the context of a number of diseases caused by infection with taxonomically diverse protozoan parasites, nematodes, and cestodes.