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 (Definition) 1  Menstrual refers to the monthly cycle in women which prepares the female for ovulation, generally once per month, which is that time of month that the egg can be fertilized by the male sperm, for the purpose of reproduction. Menstrual cycles start at the first day of menstruation.