Cell-mediated immunity in pregnant patients with and without a previous history of spontaneous abortions.

The percentage of T-cells was studied in pregnant patients with a previous history of spontaneous abortions, in patients without such a history and in nonpregnant controls. The percentage of T-cells remained unaltered during the three trimesters of normal pregnancy. In patients with a previous history of spontaneous abortions, the T-cell percentages were lower in the second and third trimesters than in non-pregnant controls, but the values did not differ statistically from corresponding values in those patients with no previous history of spontaneous abortion (normal pregnancy). The phytohaemagglutinin (PHA)-induced transformation of lymphocytes was depressed in the second and third trimesters of both patients with a normal pregnancy and those with a previous history of spontaneous abortions. Thus, while the percentage of T-cells remained unaltered during pregnancy, their response to PHA falls in the second and third trimesters.