Changes in immunologic parameters in normal pregnancy and spontaneous abortion.

To study the immunologic characteristics of miscarriage, 40 nonpregnant control subjects, 40 primigravid women in the first trimester of pregnancy, and 18 patients admitted with a spontaneous abortion were investigated. The total white blood cell count was raised significantly in normal pregnancy and spontaneous abortion (p less than 0.0005). The lymphocyte count was unchanged. The total T-cell number fell significantly in normal pregnancy and abortion (p less than 0.01). No change was seen in the cytotoxic suppressor or helper/inducer T-cell numbers. The number of activated T cells fell significantly in both groups of patients (p less than 0.0005). The response to mitogens was greatly increased in both normal patients and those with miscarriage. A marked rise in interleukin-2 receptor levels was noted in patients with spontaneous abortion (p less than 0.005). The changes in white blood cell count, total T-cell number, activated T-cell number, and mitogen activity were thought to be a direct result of pregnancy. The rise in interleukin-2 receptor levels was seen only in the miscarriage group. Although it is not known if these changes are cause or effect, it would appear that immunologic abnormalities are associated with spontaneous abortion.