A seven cell human egg recovered from the oviduct

A seven cell human egg recovered from the proximal middle quarter of the oviduct is described. Whether or not it is a normal representative of this stage of human development cannot be established at the present time. The specimen was recovered 83 hours after intercourse and 77 hours after the first significant elevation of the luteinizing hormone level in the urine. According to these data and the results of the endometrial and corpus luteum biopsies, the age of the egg was estimated to be approximately 72 hours. An analysis of size and the reaction of the blastomeres to toluidine blue suggests that they already show differentiation at this early stage of development. The addition of these findings to previous reports of eggs recovered from human oviducts and uteri gives support to the concept that human eggs are delivered to the endometrial cavity when they contain between 7 and 12 blastomeres.