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.
These chemicals, known as hormones, are human proteins with the capacity to affect and regulate human growth and function. The female reproductive cycle is a general term which encompasses the ovarian cycle, the uterine cycle, the hormonal changes that regulate them, and cyclical changes in the breasts and the cervix.