As the urinary bladder and rectum enlarge near the caudal end of the peritoneal cavity, a peritoneal recess is produced between these viscera. In the male the recess is called the rectovesicle pouch (Douglas). In the female the recess is subdivided by the uterus and broad ligament into a ventral vesicouterine pouch and a dorsal rectouterine pouch.
Source: Atlas of Human Embryos.