A single Regional Dressage Championship program organized by the United States Dressage Federation (USDF), and recognized by the United States Equestrian Federation, Inc. (USEF), will be held in each of the nine USDF.
If fertilization and/or implantation does not take place, the system is designed to menstruate (the monthly shedding of the uterine lining). In addition, the female reproductive system produces female sex hormones that maintain the reproductive cycle.
Menstrual cycle. Home Â» Menstrual cycle. Definition. noun. The reproductive cycle of human and other animal (e.g. certain primates) females, and is comprised of phases characterized by the changes in the ovarian follicles (i.e. ovarian cycle), as well as changes in the endometrial lining of the uterus (i.e. uterine cycle) Supplement.