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.
The first period is known as menarche (pronounced: MEH-nar-kee). Doctors often talk about a girl's monthly cycle â the number of days from the start of her period to the start of the next one â in terms of a 28-day cycle. But 28 is just an average figure that doctors use. Women's cycle lengths vary â some have a 24-day cycle, some have a 34-day cycle.