Morphological changes in maternal lymphocytes in pregnancy.

By use of staining with toluidine blue, the changes in the nucleoli of lymphocytes in 150 healthy women were studied. The patients were divided into five groups: non-pregnant women; women in the first, second and third trimesters of pregnancy; and women who were five days post partum. A progressive and statistically significant rise in the number of lymphocytes with micronucleoli was found during pregnancy and there was a fall after delivery. This increase was associated with a decrease in the incidence of ring-shaped nucleoli. There were no significant changes in the absolute number of lymphocytes and in "active" lymphocytes during pregnancy.