Blood basopenia as an indicator of ovulation.

Direct basophil counts were done on capillary blood samples in thirteen normal young women, during the different phases of their menstrual cycles. Mean basophil counts during the follicular and progestational phases were 36.6/cumm and 39.3/cumm respectively. A significant midcycle fall in counts of 36% and a premenstrual fall of 22% were observed. These changes are probably due to migration of the cells from the peripheral blood into the rupturing follicle of the ovary and into the ischemic premenstrual endometrium.