Unveiling The 4 Phases Of The Menstrual Cycle – Explained!

The menstrual cycle is a very integral part of a woman’s life. It prepares women for reproduction. However, this cycle is different for different women.

Some women may experience intense menstruation, while others may undergo lengthy cycles.

However, have you ever wondered what causes this bleeding? Let’s understand the detailed process and the various stages which are a part of this process.

Why Do Women Undergo Menstruation?

The female productive system has ovaries that release an egg every 30 days. It is this egg that fertilizes with sperm to form a fetus.

This confirms the pregnancy and a woman gives birth to a baby after nine months. However, not every egg is fertilized.

These unfertilized eggs leave the ovaries and travel through the fallopian tube to the uterus.

Women Undergo Menstruation cramps

Uterus often prepares itself to receive the fertilized embryo and builds up a thick lining of blood to nourish it.

But once the unfertilized egg reaches the uterus, this lining sheds down. This is what makes women bleed during menstruation.

Phases Of Menstruation

The entire cycle of menstruation is divided into four stages. Let’s understand one by one:

  • Menstrual Phase
  • Follicular Phase
  • Ovulation Phase
  • Luteal Phase
Phases Of Menstruation

Menstrual Phase

This is the first and the most crucial stage of menstruation. It commences when an egg released from the ovaries is left unfertilized.

As a result, the preparations of the female reproductive system to conceive go in vain.

The levels of estrogen and progesterone that helped develop a thick lining of blood around the uterus walls reduce to the minimum extent.

Hence, the blood lining does not sustain and breaks down. This blood is discharged from the body through the vagina.

One may tend to feel weak, clumsy, and irritated during this phase.

Follicular Phase

This is the second stage of the menstruation cycle. It starts on the first day when you receive a period. It usually stretches till the 13th or 14th day of the cycle.

This is the phase wherein the ovaries mature again to release a healthy egg. The command of the pituitary gland stimulates them.

Also known as the master gland, this pituitary gland sends signals to the ovaries through hormones. 

These hormones help the ovaries to expand their egg cells. As and when these egg cells grow, a sac-like structure called a follicle is formed.

This follicle continues growing until it matures by the end of the 13th day. This is the time when the follicle gets converted into a full-grown egg.

As the follicle matures, it also secretes hormones that trigger the uterus to form a thick lining of blood vessels.

This lining of the uterus is very important as it supplies essential nutrients, minerals, and hormones to the fertilized egg.

Ovulation Phase

This is probably the 14th day of the cycle. When the follicles mature to form an egg, the pituitary gland sends a hormone to the ovaries to release the matured egg.

This egg enters the fallopian tube after leaving the ovaries.

These tubes then carry the matured egg to the uterus. The eggs, however, cannot travel through the fallopian tubes.

They are covered by cilia, hair-like projections that help the matured egg reach the uterus easily.

Luteal Phase

This is the phase that finally begins on the 15th or the 16th day of the cycle. It continues until the cycle ends.

It is important to note that the mature egg released by the ovaries does not go to the uterus instantly. It rather stays in the fallopian tubes for at least 24 hours.

During this duration, the egg may fertilize with a sperm to form an embryo which then develops into a fetus. But if the egg does not fertilize, it disintegrates in the uterus.

On the failure to receive a fertilized egg, the uterus no longer requires the thick blood lining. Hormones are once again released to stimulate the discharge of this blood lining.

This is when the next menstrual cycle commences in women, wherein they discharge this blood lining from the body.


This is a very important process for the well-being of the female reproductive system. It is only with the help of these processes that the woman stays healthy.

However, there might be slight variations in the timings of these phases in different women.

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