What is pieriod?

PERIODS normally refered toThe menstrual cycle is a cycle of physiological changes that can occur in fertile females. Overt menstruation (where there is blood flow from theuterus through the vagina) occurs primarily in humans and Females of other species of placental mammal undergo estrous cycles, in which the endometrium is completely reabsorbed by the animal (covert menstruation) at the end of itsreproductive cycle. This article focuses on the human menstrual cycle.

The menstrual cycle, under the control of the endocrine system, is necessary for reproduction. It is commonly divided into three phases: thefollicular phase, ovulation, and the luteal phase; although some sources use a different set of phases: menstruation, proliferative phase, and secretory phase The length of each phase varies from woman to woman and cycle to cycle, though the average menstrual cycle is 28 days Menstrual cycles are counted from the first day of menstrual bleeding.Hormonal contraception interferes with the normal hormonal changes with the aim of preventing reproduction.