The Menstrual Cycle In Women

The menstrual cycle usually lasts about 25 to 32 days. However, women’s menstrual cycles vary in their length and amount of bleeding, according to the woman’s age, weight, diet, amount of physical activity, level of stress and genetics. The length of the menstrual cycle is counted from the first day of menstrual bleeding until the day before the first day of the next menstrual bleeding. The Menstrual Bleeding Phase (Days 1 to 5), also known as menstruation, menses or period. Hormone levels are at their lowest point during this phase.The hypothalamus begins to produce GnRF because of the low levels of estrogen and progesterone in the blood. ovarian follicles enlarge during the first week of each menstrual cycle.

They produce estrogen and begin

The Progesterone Phase (Days 15 to 28). The empty dominant follicle in the ovary changes into a corpus luteum (which produces progesterone and some estrogen) because of stimulation resulting from the high level of LH released by the anterior pituitary gland. If the ovum is not fertilized, the activity of the pituitary is inhibited because of the high level of progesterone in the blood produced by the corpus luteum. The pituitary production of LH is then reduced.

The corpus luteum is a reorganization of the cells from the ruptured egg follicle. The corpus luteum steadily produces and secretes progesterone. The corpus luteum also produces small amounts of estrogen during this phase. As progesterone secretion increases, LH secretion decreases. The corpus luteum begins to degenerate by Day 23 to 24 because the LH level is low. Thus, the production of estrogen and progesterone also declines. the blood supply to the endometrium continues to increase due to the rising levels of progesterone produced by the corpus luteum of the

These nutrients can nourish a fertilized ovum until it is implanted. Progesterone and estrogen in the blood decrease toward the end of this phase because of the degenerating corpus luteum. The endometrial cells cannot receive the oxygen and nutrients that the blood vessels carried, and they begin to die. The Menstrual Phase begins, and menstrual bleeding occurs. Shortly before, during or after ovulation, the BBT rises due to the increase in progesterone production. The BBT remains elevated until progesterone levels drop and the Menstrual Phase