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How do I Determine Menstruation Cycle Length?

Nicole Madison
Nicole Madison
Nicole Madison
Nicole Madison

Menstruation cycle length varies from woman to woman. Typically, you can determine menstruation cycle length by counting from the first day of vaginal bleeding in one cycle to the day before the first day of vaginal bleeding in the next cycle. This differs from the length of your menstrual period, which is usually counted from the first day of menstrual bleeding to the last day of bleeding within a menstrual cycle. Often, discussions of menstruation cycles include 28-day cycles, but this is not accurate for all women; a normal menstrual cycle may range from about 21 days to about 35 days in length. At times, however, women may have cycle lengths that are shorter or longer than these for various reasons.

When you are trying to determine your menstruation cycle length, it is important to keep in mind that a menstrual cycle includes not only your period, but also all the other days between menstruation and your next period. You can determine the length of your menstrual cycle by beginning your count on the first day of your menstrual period and ending your count with the day before your next menstrual period. For example if you begin counting on the first day of a period and your next period begins on day 28, your menstrual cycle is 27 days long.

For most women, the entire menstrual cycle lasts about 28 days.
For most women, the entire menstrual cycle lasts about 28 days.

Sometimes people confuse menstruation cycle length with menstrual period length. The two are not the same, however. Typically, you will count menstrual period length by beginning with the first day of your menstrual period and stopping with the last day of menstrual bleeding. Many women have periods that last for about five days, but longer or shorter periods are normal as well.

A menstrual cycle includes not only the menstrual period, but also all the other days between menstruation and a woman's next period.
A menstrual cycle includes not only the menstrual period, but also all the other days between menstruation and a woman's next period.

Once you have determined the length of your menstrual cycle, you may wonder whether it is normal. Typically, menstrual cycles that range from 21 days to 35 days in length are considered normal. Every woman is different, however, and it is possible that a longer or shorter cycle may still be normal for you. Sometimes, however, menstrual cycles are longer or shorter than normal because of some type of problem. For instance, a hormonal imbalance or delayed ovulation may cause changes in menstruation cycle length; even physical or emotional stress may cause changes in your cycle length.

A woman's menstrual cycle length may not be the same every month.
A woman's menstrual cycle length may not be the same every month.

It is important to note that your menstrual cycle length may not be the same every month. Your menstrual cycle could last for 27 days one month and then 25 the next. For this reason, you may use averaging to determine your typical cycle length. To do this, you may add the lengths of your last four cycles and then divide this number by four. Your answer is the average length of your menstrual cycle.

Nicole Madison
Nicole Madison

Nicole’s thirst for knowledge inspired her to become a WiseGEEK writer, and she focuses primarily on topics such as homeschooling, parenting, health, science, and business. When not writing or spending time with her four children, Nicole enjoys reading, camping, and going to the beach.

Learn more...
Nicole Madison
Nicole Madison

Nicole’s thirst for knowledge inspired her to become a WiseGEEK writer, and she focuses primarily on topics such as homeschooling, parenting, health, science, and business. When not writing or spending time with her four children, Nicole enjoys reading, camping, and going to the beach.

Learn more...

Discussion Comments

Wisedly33

@Scrbblchick -- Nearly every woman I've known who had a long cycle and long periods had really bad periods. It has to be a hormonal thing and birth control evens out the hormones, so the cycle normalizes, and so do the period symptoms.

Women need to be very familiar with their cycle durations. Sometimes, a problem will crop up in a late or early cycle before it does anywhere else. Having early or late periods consistently if the woman has always been very regular before could be a sign of something amiss and the woman should see her doctor.

Scrbblchick

One thing the article didn't mention is that a woman's cycle may not be the same number of days every month. It's probably more helpful to keep track of the cycle for at least six months so the woman can get a really good idea of what's normal for her.

Before I started taking birth control pills, my cycles ran at 32-36 days and I had eight-day periods. Let me tell you -- that is no fun, whatsoever. Seems like all I did was spend my time either getting ready to start my period, or just finishing it. There was maybe one week a month for years when I really felt good. I'm one who really took to birth control. It changed my life!

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    • For most women, the entire menstrual cycle lasts about 28 days.
      By: designua
      For most women, the entire menstrual cycle lasts about 28 days.
    • A menstrual cycle includes not only the menstrual period, but also all the other days between menstruation and a woman's next period.
      By: reineg
      A menstrual cycle includes not only the menstrual period, but also all the other days between menstruation and a woman's next period.
    • A woman's menstrual cycle length may not be the same every month.
      By: picsfive
      A woman's menstrual cycle length may not be the same every month.
    • An woman with an eating disorder may experience irregular menstruation.
      By: Sylvie Bouchard
      An woman with an eating disorder may experience irregular menstruation.
    • Most girls start to menstruate between the age of 10 and 15 years old.
      By: Maya Kruchancova
      Most girls start to menstruate between the age of 10 and 15 years old.