Menstrual Cycle (Periods)

What is menstruation?

Menstruation (or a period) is when a woman bleeds from her vagina for a number of days. For most women, this happens every 28 days or so. Menstruation is one part of the menstrual cycle. The menstrual cycle involves changes in a woman’s body that happen when an egg develops and the body prepares for a possible pregnancy.

  • the menstrual cycle starts when a woman has a period
  • the first day of bleeding is called day one
  • the cycle ends the last day before the next period starts
  • a normal cycle can range from 3 to 6 weeks (21-42 days, average 28 days)
  • a normal period can range from 3 to 7 days

Like the menstrual cycle, the menstrual period is different for each woman. Stress, weight loss, exercise and travelling can affect the length of the cycle.

What happens during the menstrual cycle?

  1. At the beginning of the menstrual cycle about 10 to 20 eggs start developing. These eggs produce the female hormone oestrogen, which causes the lining of the uterus (endometrium) to thicken and prepare for a pregnancy.
  2. Only one or two of the eggs mature and are released from the ovary and travel through the fallopian tubes towards the uterus. This is called ovulation. If sperm are not around to fertilise the egg, it disappears over 12-24 hours; if the egg is fertilised by a sperm it reaches the uterus in about a week.
  3. If the fertilised egg attaches to the lining of the uterus, the woman is pregnant. After ovulation, a hormone called progesterone is produced to make the lining of the uterus suitable to support pregnancy. If there is no pregnancy, production of progesterone ceases after 14 days and the lining of the uterus breaks down and flows out through the cervix and the vagina as a menstrual period.
  4. The whole cycle then starts again.

What happens to cervical mucus during the cycle?

Throughout the menstrual cycle, the cervix (the neck of the uterus) produces mucus. The type of mucus changes throughout the menstrual cycle depending on the levels of oestrogen and progesterone:

  • fertile time - mucus becomes thinner, clearer, wetter and more slippery
  • non-fertile time - mucus is more sticky or gummy, is usually white or yellowish in colour and sperm find it hard to move through this kind of mucus

Some women can get pain in the lower abdomen or some light vaginal bleeding at the time of ovulation (egg release).

If you use a fertility awareness method of contraception, and you note these cervical mucus changes it can help you work out when you’re fertile.

What happens during menstruation?

  • the average menstrual period lasts from about 3 to 7 days
  • the amount of blood loss can vary from cycle to cycle and from woman to woman
  • less than half of the menstrual fluid is blood.
  • this regular loss of blood is why women need more iron in their diet to replenish red blood cells
  • the menstrual flow usually starts heavier (usually bright red) and tapers off (dark red or brown) as the period gets lighter at the end

The first period is called menarche. In Australia it usually happens between 9 and 14 years of age. Periods continue until menopause, when women are between 45 and 55 years of age. In Australia the average age of menopause is 51 years of age.

Some women avoid having sex during their period. This can be for personal, religious or cultural reasons. Having sex during periods is not dangerous unless a woman has an infection such as hepatitis B or C, which is carried in the blood and can be more easily spread to her partner at this time.

What menstrual protection is available?

Sanitary pads (or napkins)

Pads should be changed every 3 or 4 hours - used pads should be wrapped and placed in a rubbish bin. They should never be flushed down the toilet as they will block the plumbing system. Some women prefer to use cloth pads which can be washed and reused.


Tampons are small cylinders made of cotton (or cotton and synthetic material) which are placed inside the vagina and absorb the menstrual flow. Many women prefer tampons because you can go swimming when you have your period and they are less obvious under tight-fitting clothes.

Tampons can be used by women who are not yet sexually active, though they may find it more difficult at first to insert the tampon comfortably.

You can’t feel a tampon which is put in properly, and it’s impossible for a tampon to get lost inside the vagina as there is a string attached to the tampon to pull it out.

Tampons should be changed every 3 to 4 hours - used tampons should be wrapped and placed in a bin. They should never be flushed down the toilet as they will block the plumbing system.

There is a very rare disease that can be associated with tampon use called toxic shock syndrome. Symptoms include a high fever, rash, headache and generally feeling very unwell. The risk of toxic shock syndrome can be reduced by washing your hands carefully before inserting a tampon, by changing tampons regularly and not ever leaving tampons in place for more than 8 hours – if you choose to use a tampon overnight it is useful to set a phone reminder to prompt you to change it as soon as you wake up.

Menstrual cups

A menstrual cup, such as The Lunette or DivaCup, is a small silicone cup placed in the vagina. It collects several hours of menstrual flow and is emptied as needed throughout the day. It is rinsed in water and can then be reused and lasts for several years and costs around $50. Make sure you follow the manufacturer’s instructions about how long to use the cup and only use trusted brands as very rare cases of toxic shock syndrome have been associated with these products.

It may appeal to women who are environmentally conscious or to travellers in areas where it is difficult to buy or dispose of pads and tampons. Follow the manufacturer’s instructions about how to care for your menstrual cup.

Period underwear

Period underwear, such as Modibodi or Thinx, have an absorbent layer in the gusset which is protected by a leakresistant layer. The underwear is washable and can be used on their own or together with other sanitary protection.

For more information

Family Planning NSW or 1300 658 886
National Relay Service (for deaf people) – 13 36 77
TIS National’s interpreting service131 450
Visit your nearest Family Planning NSW

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