Host defense during pregnancy: neutrophil chemotaxis and adherence.

Pregnancy is associated with impairment in several immunologic functions that effect the outcome of certain infectious and autoimmune diseases. Previous studies have indicated that pregnant women have decreased neutrophil motility, but results are discordant. We performed a longitudinal study of polymorphonuclear leukocyte chemotaxis using a micropore filter assay and polymorphonuclear leukocyte adherence using a nylon wool column assay in 58 women during pregnancy, delivery, and the postpartum period. Polymorphonuclear leukocyte chemotaxis was decreased significantly in pregnant women during the second (-20%) and third (-17%) trimesters and 1 to 3 months post partum (-18%), but not during the first trimester (-6%) compared with nonpregnant control subjects. The impairment in polymorphonuclear leukocyte chemotaxis appeared to be a cell-associated rather than a humoral defect. Polymorphonuclear leukocyte adherence was decreased significantly in pregnant women during the third trimester (-16%). These data may help explain the increased incidence of infection and amelioration of certain immunologically mediated illnesses during pregnancy.