A woman usually starts having periods (menses) between the ages
of 11 and 13. They are caused by a small amount of blood being
released from the womb (uterus) through the cervix and out through
the vagina. This blood is due to a natural shedding of the lining
of the womb. In some women, they may initially be irregular,
although most settle to a regular pattern.
Periods usually continue until the ovaries stop producing
estrogen hormone between 45 and 55 years of age. See our
section on the menopause.
The length of a period is normally between 3 and 7 days. The
length between the start of one period and the start of the next (a
menstrual cycle) is different for each woman, but is usually
between 21 and 35 days.
In some women this cycle can become irregular. There are many
causes, including hormonal imbalances and side effects of
Periods can sometimes be painful, with pain in the lower abdomen
and/or pelvis or cramps. Some women are aware of an increased blood
flow and for some this is problematic with flooding and clots
If you are concerned about painful or heavy periods, please
discuss this with your GP or a nurse or doctor at any Sandyford clinic.
There are many treatment options available for heavy and/or painful
periods. These options include non-hormonal tablets and in only
very few cases is a hysterectomy (removal of the womb)
Periods discontinue during pregnancy. There are other causes for
your periods stopping and it is advisable to contact us or your GP
for further investigations if your periods stop and you are not
You can find out useful information about periods for young
people at: http://www.brook.org.uk/my-body/girls-and-young-women/periods