To prevent menstruation, the cells of the blastocyst release _____ for the first _____ months of pregnancy. This promotes the survival of the corpus luteum until the placenta is mature enough to produce large amounts of _____ and _____.

3000+ review questions on anatomy and physiology. 

Anatomy refers to the internal and external structures of the body and their physical relationships, whereas physiology refers to the study of the functions of those structures.