Menstrual Cycle
Menstruation Cycles, Phases and Changes Explained

monthly menstrual cycle

menstrual chart

28 Day Menstrual Cycle Chart

Menstrual Cycle

Contents

What Is A Menstrual Cycle?
How Long Is It?
What Is The Follicular Phase?
What Is the Ovulatory Phase?
What Is the Luteal Phase?
Young Girls: What’s a Normal Cycle?
Menopause: When Do Changes In The Cycle Start?
When Do Menstrual Cycles Return After Pregnancy?
What Can Cause Changes In Cycles?



Related Articles:


Guide to Menstruation
Female Body Diagrams

What Is A Menstrual Cycle?

A menstrual cycle is the monthly process which occurs in the female body and results in a period. It begins with the release of a fertile egg (ovum) from the ovary, and the lining of the uterus thickens in preparation for pregnancy. If fertilization does not occur the lining of the uterine sheds and a vaginal bleed results. Many women use a menstrual cycle chart or calculator to track their cycle. This helps to pinpoint ovulation which is the most fertile time of the month to conceive.

How Long Is It?

The average menstrual cycle is 28 days long and is measured from the first day of your period to the first day of the next one. However depending on the individual woman a menstrual cycle can last anywhere between 21 days and 38 days. A menstrual flow normally lasts 3 to 7 days.

What Is The Follicular Phase?

This is the first phase of the menstrual cycle, and is also called the preovulatory or proliferative phase. During the follicular phase of a menstrual cycle, the brain releases hormones which stimulate the growth of follicles in the ovary to produce a mature egg. Those hormones are called follicle stimulating hormones (FSH) and luteinizing hormones (LH). Follicles are little cells in the ovaries, each one contains an egg. In the follicular phase some of these follicles begin to grow as the egg inside them matures in preparation for release. By the time of ovulation only one follicle has grown big enough to burst open and release it's egg. If you saw the follicle on an ultrasound scan it is usually about 22 to 25 millimeters in size at the time of ovulation. A follicle cyst is where the follicle does not burst open, but instead grows and becomes fluid filled. See functional cysts for more details.

What Is the Ovulatory Phase?

This is the second stage of the menstrual cycle. The LH hormones stimulate the ovaries to produce estrogen, which then prompts the lining of the wall of the uterus (endometrium) to thicken in preparation for pregnancy. Meantime the estrogen also triggers a surge in the production of LH which causes the follicles of the ovary to rupture, resulting in the release of a mature egg. The egg travels into the fallopian tube where it is ready for fertilization if it meets sperm. Only one mature egg is normally released. This process is called ovulation. Some women experience slight cramping or spotting during ovulation, which is also called mittelschmerz (middle abdominal pain).

What Is the Luteal Phase?

The luteal phase is the third and final stage of the menstrual cycle. This phase begins directly after ovulation and ends on the first day or the period. Generally it starts on day 14 of the menstrual cycle and lasts between 10 and 16 days. The hormones estrogen and progesterone increase and combine to create changes in the endometrium (uterus lining) to prepare it to accept an embryo, should conception occur. The thickened endometrium emits substances (including prostaglandin) which scientists think cause premenstrual syndrome (PMS, formerly known as PMT) such as cramps, mood swing and lower back pain. The body temperature rises to create optimum conditions for pregnancy. When trying for a baby, many women used a basal temperature chart to track those rises in temperature to help predict their own luteal phase and day of ovulation. When fertilization does not occur, mucus secreted by the glands of the cervix becomes suddenly creamy, tacky or sparse (depending on the woman) until menstrual bleeding begins. See also: Treatment for PMS.

Young Girls: What’s a Normal Cycle?

The first menstruation of a young girl is known as menarche. This can occur anywhere between the ages of 10 and 15, although it may occur as young as 8 and as late at 17. A girl's first period usually occurs two years after her breasts begin to develop. Menstrual cycles may be irregular for the first year, some may last only 24 days, others up to 45 days. It is also common to miss a month altogether, but this is nothing to worry about.

Menopause: When Do Changes In The Cycle Start?

Irregular periods are a common symptom of perimenopause. Women over 35 are candidates for perimenopause and technically menopause is considered when a woman misses her period for 12 consecutive months. It is rare for a woman to experience normal cycles and then a sudden stop at menopause. More commonly changes start occurring in the cycle 5, 10 or even 15 years before reaching menopause. Some women find that they may have suffered from painful periods throughout their 20s and 30s, but less so in their 40s. Menopause can typically happen anytime between 45 and 55.

When Do Menstrual Cycles Return After Pregnancy?

Approximately 80 percent of women notice a return to regular menstrual cycles within 10 weeks of childbirth. However, women who choose to breastfeed may find that it takes up to 20 weeks for ovulation and missed periods to return. It is also common for periods to be irregular or heavier than normal, but this usually settles down after a few cycles.

What Can Cause Changes In Cycles?

It is important to note that minor changes can happen in a menstrual cycle at every age. It is rare for a woman to experience no disruption to menstrual cycles during her reproductive years, given the complex role of hormones in the process. Stress, travel, illness, extreme dieting can cause heavy periods or irregular periods, as well as causing menstruation to be missed altogether. In a healthy adult, the most common cause of a consistent change in a menstrual cycle is pregnancy and menopause. If these are ruled out, other possible causes include polycystic ovary syndrome (PCOS), endometriosis, PID and uterine fibroids and some female cancers such as endometrial cancer and cervical cancer. Always consult your doctor if in doubt. For more details see also, what can cause a change in my monthly cycle?

Related Questions
When should my periods start? - Menarche, the first period.
How can I relieve period cramps? - For pain that recurs every month.
Planning a special vacation or honeymoon? You may wonder:
Can I delay my period without taking the pill?

  Related Articles on MENSTRUAL CYCLES

For more reproductive issues, see the following:

Premenstrual Dysphoric Disorder (PMDD)
Menopause Testing

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