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Understanding your menstrual cycle

What is the menstrual cycle?

When we talk about the menstrual cycle the first thing many of us think of is 'periods'. The period (menstruation) is just part of a continuous cycle of changes in the body that is regulated by hormones.

The cycle usually begins during the teenage years and continues until the menopause, at about the age of 50. The purpose of the menstrual cycle is to prepare the body for reproduction.

What is the normal cycle?

The menstrual cycle can vary from woman to woman. For some it is normal to have a shorter cycle (eg. 21 days) and for others a longer cycle (eg. 35 days). The average for all women in the world is 28 days.

This means that the time of ovulation varies, but the average is the 14th day.

The periods can last from 1 to 8 days, with the average being about 4 days.

What causes irregularity of the periods?

The cycle will vary in a woman from time to time. This can be the result of emotional stress, illness, travel, sudden weight change or the use of some medicines.

What are some of the problems?

Many women will experience problems with their menstrual cycle at some time in their life. The commonest problems are period pain, premenstrual tension, irregular periods and very heavy periods.

If you have any problems or questions about your menstrual cycle, discuss them with your doctor.

When is pregnancy likely to occur?

You are most likely to get pregnant between the 8th and the 18th day, depending on when you ovulate and how long the sperm remain active. It is useful to know when you ovulate-you may feel a pain in the abdomen and notice that your vaginal mucus changes from jelly-like to watery. Intercourse at this time and for the next 2 days is most likely to cause pregnancy.

Copyright 1995: John Murtagh, Professor of General Practice
Monash University, Melbourne, Australia