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  • Writer's pictureShruti GOCHHWAL

The Four Phases of the Menstrual Cycle


Picture of female reproductive organ, Credits: Pixabay

Menstrual Cycle: What is it?

Menstrual cycle

Phases of the menstrual cycle, Credits:

The menstrual cycle occurs in a woman of reproductive age.  It is a natural change that occurs in the female body every month that makes pregnancy possible. Medically, menstruation is a process where a woman experiences discharge of blood and tissues from the lining of the uterus. This occurs every month, except during pregnancy and the process lasts for about 3-5 days.

A typical cycle of menstruation consists of several stages where the female body undergoes various hormonal changes to prepare for the possibility of becoming pregnant each month. Hormone fluctuations are responsible for transitioning the body from one phase to the next.

What are the Four Phases of the Menstrual Cycle?

It has been found through various researches that an entire menstrual cycle usually lasts between 24 and 38 days.  The length of the menstrual phase may vary from cycle to cycle, and may also change over the years. The four phases of the menstrual cycle are listed below:

  1. The menstrual phase

  2. The follicular phase

  3. The ovulation phase

  4. The luteal phase

Menstrual Phase (Day 1-5)

The first stage of the menstrual cycle is the menstrual phase where you start noticing your period. During your period, you release a combination of blood, mucus, and soft tissue from your uterus.

In this phase, the unfertilized egg from the previous cycle sheds down through your vagina. The uterus lining which is being prepared to support your pregnancy also sheds down. During this phase, you may also experience a drop in estrogen and progesterone hormones.

During the menstrual phase, you may experience symptoms like abdominal cramps, tender breasts, bloating, mood swings, backaches, tiredness, headache and irritability.

Follicular Phase (Day 1-13)

The follicular phase also starts with the menstrual phase and ends with ovulation. This phase usually lasts for 13 days. During the follicular phase, a course of events takes place.

  1. The hypothalamus is stimulated to release hormones by the pituitary gland which helps egg cells in the ovaries to grow and develop.

  2. The follicle-stimulating hormone released by the pituitary gland stimulates the ovaries to produce around 5-20 follicles containing immature eggs.

  3. One of these eggs will mature while the rest may be reabsorbed by your body. In rare cases, two eggs may also mature sometimes. It takes 13 days for the egg cell to reach maturity.

  4. While the egg cell matures, the follicle secretes estrogen hormone that stimulates the uterus to develop a lining of blood vessels called the endometrium.

Ovulation Phase (Day 14)

Estrogen released during the follicular phase triggers the pituitary gland to release another hormone called luteinizing hormone which marks the start of ovulation phase.

  1. During the ovulation phase, the ovary releases the matured egg.

  2. The released egg cell is swept into the fallopian tube which travels down the fallopian tube towards the uterus to be fertilized by the sperm.

  3. Ovulation period is the time when a woman can get pregnant.

  4. Symptoms like a slight rise in body temperature followed by a thick discharge can be noticed during the ovulation phase.

Luteal Phase (Day 15-28)

The luteal phase begins after the ovulation phase on the 15th day and lasts until the end of the cycle. During this period the egg cell released during the ovulation phase changes into corpus luteum. This stimulates the release of progesterone and estrogen hormone. These hormones help keep the uterine lining thick and ready for a fertilized egg to implant. The egg remains viable for around 72 hours, and if the egg is not fertilized during this period, the egg cell disintegrates. The corpus luteum will shrink away and be resorbed, estrogen and progesterone levels drop and cause the onset of your period. This causes the menstrual phase of the next cycle to begin.

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