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.
Safe Period Calculator : Hypothesis. The menstrual cycle, is commonly divided into three phases: the follicular phase (pre-ovulatory phase), ovulation, and the luteal phase (post-ovulatory phase). The length of each phase varies from woman to woman and cycle to cycle, though the average menstrual cycle is 28 days.