A study of total platelet count, adhesive platelet count and platelet adhesiveness in various phases of normal menstrual cycles.

The fact t,hat among other changes, menstruation involves bleeding from the blood vessels injured at the shedding of the uterine mucosa has directed special interest to the blood changes which attend the phases of menstrual cycles. Demonstrable fall in the platelet count at the time of menstruation (Pfeiffer and ,Hoff, 1929) and the simultaneous lowering of capillary resistance (Henning, 1924) have given rise to the speculation. that menstruation is to be regarded as a physiological thrombopenia with a general liabilit.y to bleeding as a latent haemorrhagic diathesis. The correlation of mid-cycle peak elevation of platelet count with the basal temperature shift from lower to higher phase (Peeper and Lindsey, 1956), led to the belief that the former may be more accurate indication of ovulation than the latter. The occurrence of thromboembolic episodes in 'pill-users' have led -to the speculation about the possible role of progestational compounds as its aetio-