The amount of blood that comes out of a woman's body is called menstrual flow.
The amount of blood that comes out of a woman’s body is called menstrual flow.

The entire normal menstrual cycle usually lasts between 24 and 38 days. However, the cycle between 21 and 45 days is still considered normal. It may vary from cycle to cycle in every woman and may also change over the years.

In a normal cycle of menstruation, there are some events occurring in the ovary and womb (uterus). World Health Organization considered three different phases in a normal cycle of menstruation based on fertility stages:

  • Relatively infertile phase: This is the time before the ovary releases eggs (ovulates), and women are unlikely to get pregnant. The vagina becomes dry, the ovary prepares an egg to be released, and the estrogen level increases in the blood.
  • Fertile phase: This phase begins before, during, and immediately after the ovary releases the egg, and in this phase, women are likely to get pregnant. In this phase, the estrogen level is high. The vagina becomes wet and secrets thick lubricating fluids. The ovary releases an egg (ovulation) 14 days before the menses. The egg remains alive or fertile for 24 hours. In this phase, if sexual intercourse occurs, then the sperm can live up to one to three days.
  • Infertile phase: In this phase, if fertilization occurs, the womb supports the egg for implantation. If pregnancy doesn’t occur, the lining of the womb starts shredding off and discharging through the vagina, which we call menses. In this phase, women cannot become pregnant.

Women are considered fertile if they can produce the egg (woman’s sex cells), become pregnant, and carry the pregnancy to live birth. The couple’s combined fertility is based on the phases of a woman’s menstrual cycle, her signs and symptoms of fertility, and the length of time the sperm and egg releases.

What does menstruation mean?

Menstruation (menses or period or monthly) is the discharge of blood and tissue from the inner lining of the womb through the woman’s vagina every month. The amount of blood that comes out of a woman’s body is called menstrual flow.

In the United States, the average age of girls having their first menses (menarche) is normally between 12 and 13 years. The average length of menstrual flow can be seven days or less in women, and they may normally need to change three to six pads or tampons per day. Some women can predict the day and time of their period if they are very regular. Light, moderate, or heavy blood flow are all considered normal. Women stop menstruating permanently at an average age of 40-45 years; this is called menopause.

What does menstrual cycle mean?

The menstruation cycle is the cycle of physical changes in a woman’s sex organs (ovary and womb) that begin on the first day of menses and end when the next menses begins.

During the cycle, the ovaries naturally produce chemical substances called hormones (estrogen and progesterone) that are circulated through the body in the bloodstream. These hormones are signals that are sent back and forth between the brain and ovary. It causes various signs and symptoms in a woman (bloating, acne, breast tenderness, etc.), and it changes throughout the menstrual cycle. Levels of these hormones can detect fertility in a woman.


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When to see a doctor?

You must see a gynecologist if your menses

  • Have not started within three years after breast growth.
  • Have not started by 14 years of age with excessive hair growth on face and chest or if you have an eating disorder.
  • Have not started within 15 years of age.
  • Occur more frequently in less than 21 days.
  • Occur more than 45 days apart.
  • Occur 90 days apart even for every cycle.
  • Last more than seven days.
  • Are heavy and require a frequent change of pad (>1 every one to two hours).
  • Are related to a history of excessive bruising or bleeding or a family history of a bleeding disorder.

What are the factors that affect the normal menstrual cycle?

The factors that affect include:

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Medically Reviewed on 10/13/2020

The American College of obstetricians and Gynaecologists

WHO: Natural family planning: what health workers need to know

Office on Womens Health: