The menstrual cycle is a completely natural, reoccurring hormonal cycle women of reproductive age go through every 28-30 days. This cycle has 4 main hormones: Estrogen, Progesterone, Follicle-Stimulating Hormones and Lutenizing hormone. These reproductive hormones each play a key role in this delicate cycle. The main purpose of our menstrual cycle is to prepare the body for a potential pregnancy.
Menstruation (Day 1-5):
Hormones: Low estrogen and progesterone.
The menstrual cycle begins with menstruation, which is the shedding of the uterine lining. During this phase, estrogen and progesterone levels are low. The low hormone levels signal the body to release Follicle-Stimulating Hormone (FSH), which stimulates the growth of ovarian follicles.
Follicular Phase (Day 1-13):
Hormones: Rising FSH levels lead to an increase in estrogen.
FSH stimulates the development of ovarian follicles. Each follicle contains an immature egg (oocyte). As the follicles grow, they produce increasing amounts of estrogen, which helps thicken the uterine lining in preparation for a potential pregnancy. As estrogen levels rise, they inhibit the release of FSH and stimulate the production of Luteinizing Hormone (LH).
Ovulation (Day 14):
Hormones: A surge in LH and a peak in estrogen.
Around the middle of the menstrual cycle, a surge in LH triggers the release of a mature egg from one of the ovarian follicles. This is known as ovulation. The peak in estrogen just before ovulation helps prepare the reproductive tract for fertilization.
Luteal Phase (Day 15-28):
Hormones: High levels of progesterone and some estrogen.
After ovulation, the ruptured follicle transforms into a structure called the corpus luteum. The corpus luteum produces high levels of progesterone, which is essential for maintaining the thickened uterine lining, making it a hospitable environment for a potential embryo. If fertilization and implantation do not occur, the corpus luteum begins to degenerate, and hormone levels drop, leading to the start of menstruation.