Intra-uterine system
What is it and how does it work?
A small plastic T-shaped device, with threads attached to the end. It is fitted into the womb, with the threads hanging a little way down from the womb into the top of the vagina.
Contains the hormone progestogen, and works by steadily releasing progestogen into the bloodstream. This causes the thickening of the mucus from the woman's cervix which makes it difficult for the sperm to reach an egg. It also causes changes in the woman's body which make it less likely that the womb will accept a fertilised egg, and occasionally stops the woman's ovaries from releasing an egg.
What are the advantages of it?
Highly effective and doesn't interfere with sex. It works for 5 years and you don't have to think about contraception for as long as it is in place (the IUS does not however protect you against sexually transmitted diseases, so you may need to use condoms as well). After you have used an IUS for about 3 months, your periods usually become lighter and shorter, and an IUS usually reduces or gets rid of period pain. Some women may find that their periods stop altogether - this is perfectly healthy.
Possible side effects
Disadvantages of the IUS include:
- possibility of slight irregular bleeding between periods for the few months
- possibility of the IUS being pushed out by your womb (this is called "expulsion") or can move ("displacement"). Your doctor or nurse will teach you how to check your IUS threads every month to ensure it is still in place
- on rare occasions, the IUS can perforate the womb or cervix when it is fitted. If this happens the IUS may have to be surgically removed.
Possible temporary side effects such as:
- headaches
- acne
- breast tenderness
- cysts on the ovaries may occur for the first few months.
Who can use them?
Not everyone can use IUS, and a doctor or nurse will ask you about your own, and your family's medical history. You should mention any illness or operation you have had.
Where can you get them from?
Family planning clinics, and some GPs will fit an IUS.
The doctor or nurse will examine you internally to find the position of your womb before they fit an IUS, and will ensure there is no chance that you are already pregnant.
You will need to have your IUS checked by a doctor or nurse 4-6 weeks after it is put in and then once a year after that. An IUS can stay in for 5 years, although a trained doctor or nurse can take the IUS out at any time.
How effective is it?
The IUS is over 99% effective.
Contacts
The contacts database contains details of organisations that may be able to offer information or assistance on this issue.
Search the database »
Other forms of contraception:
Adapted from information produced by the FPA - www.fpa.org.uk
