What is a menstrual cycle?

The menstrual cycle is a repeating cycle of body changes controlled by hormones that cause a regular bleed. This bleed, which usually occurs monthly, comes from the uterus (womb) and flows out the vagina. Period, menstruation or menses, are all words used to describe the blood loss women experience at this time.

The menstrual cycle begins at menarche (the first period) and ends with menopause (the final period).The average age of menarche in Western countries is 12-13 years, but can start as early as nine and as late as 16. The average age of menopause is 51 with a range from 45-55 years (seeMenopause257.93 KB fact sheet for more information).

Note: Every woman's cycle is unique and individual in its experience

Why do I have a menstrual cycle?

The role of the menstrual cycle is to prepare the body for pregnancy. When a pregnancy does not occur a period results. On average, women in Australia have 450-500 periods in their lifetime.

How does the menstrual cycle occur?

The menstrual cycle occurs due to a complex relationship between hormones from the brain and ovaries, which leads to the development and release of an egg from the ovary (ovulation) and growth of the internal lining (endometrium) of the uterus, to prepare it for pregnancy. When the hormones signal the uterus that there is no pregnancy, the lining starts to breakdown and separate from the wall of the uterus and the period begins. Once the lining has separated from the wall of the uterus the cycle starts again.

In the first two or three years after a girl's period has started, the cycles can be irregular as ovulation does not always occur each cycle. Over the first few years, the body develops a routine of releasing an egg and shedding the lining of the uterus.

The same process, 'winding down', happens at the end of a woman's reproductive phase prior to menopause, this is known as perimenopause (seePerimenopause256.55 KB fact sheet for more information).

How long is a normal menstrual cycle?

Menstrual cycles vary between women and are measured from the first day of the period to the first day of the next period. In adolescents a cycle may be as long as 45 days, however by the 20-30s a cycle is usually between 21-38 days.

For a 28 day cycle:

What should I expect during my period?

The bleeding can vary in quality and quantity, from a small amount to a heavy loss, and can vary in colour from black/brown to bright red. The period may last from four to eight days, and most women lose less than 80mlof blood (about four tablespoons in total).

The flow changes throughout the period and can be heavier for the first three days and then lighter in the next few days. The period contains blood, mucous and some endometrial cells. Some small clots may be normal, but if the clots become frequent or larger, see your general practitioner.

The flow changes throughout the period and can be heavier for the first three days and then lighter in the next few days. The period contains blood, mucous and some endometrial lining cells. Some small clots may be normal, but if the clots become frequent or larger, see your general practitioner (GP).

In some women, at the time of ovulation (release of an egg), which usually occurs about two weeks before the next period, there may be some slight spotting and/or pain. This is due to a normal change in some of the hormones following ovulation. If pain or bleeding consistently lasts longer than three days you may need to see your GP.

What sanitary products can I use during my period?

Pads: also known as sanitary pads or napkins. These are made of absorbent material and come in a range of thicknesses and shapes. If you find that using pads cause irritation, you may need to use pads that are made from 100 per cent cotton and are scent free. Pads need to be changed usually three to four hourly. Reusable, environmentally friendly pads are also available.

Tampons: are absorbent 'plugs' made of cotton, or a combination of cotton and a synthetic material. Tampons are inserted into the vagina and are available in various sizes. They can be used by all ages and should be changed every three to four hours. Very rarely, Toxic Shock Syndrome can occur when using tampons. This is due to a rapid growth of normal bacteria releasing a toxin which leads to symptoms of 'shock' such as feeling unwell, fever, rash, diarrhoea and headache. Never keep a tampon inserted in your vagina for more than eight hours and always wash your hands before inserting.

Menstrual Cup: has been available for many years and is long-lasting (up to 5-10 years) but is used by a very small number of women. The menstrual cup (made out of either rubber (latex), silicone or thermoplastic rubbers) sits in the vagina over the cervix and collects the menstrual flow. It can be washed after each period using fresh or soapy water only. Menstrual cups are considered environmentally friendly, as they are reusable.

Will I have any signs or symptoms before my period?

Premenstrual symptoms may occur in the one to two weeks before your period. Symptoms may include irritability, bloating, sore breasts, pimples and tiredness. Normally these symptoms might be irritating but would not interfere with your day to day activities. They usually settle when the period starts or in the first two to three days of the period. In 15-20 per cent of women, symptoms can be so severe that their lifestyle is impaired and they cannot function properly (see Premenstrual Syndrome (PMS)266.58 KB fact sheet for more information). If this occurs, seek assistance from your GP.

Can I have sex during my period?

There is no medical reason why women can't have sex during their period. Some women prefer not to because of personal, cultural or religious preferences. Practicing safe sex is important at any time to prevent contracting sexually transmissible infections such as Chlamydia, HIV or Hepatitis B. Pregnancy can still occur at this time.

Conclusion

Your menstrual cycle is a normal process for your body. Each woman experiences her menstrual cycle differently, most without any difficulties. If there is any change in the cycle that worries you, see your GP.

Where can I get more information?

www.jeanhailes.org.au
www.healthforwomen.org.au
www.betterhealth.vic.gov.au

Content updated April 2012