The Intrauterine System (IUS)
This is a Long Acting Reversible Contraception (LARC). LARC methods do not rely on you remembering to use them.
An IUS is a small T shaped plastic device which contains progesterone (a hormone that women produce from their ovaries). The device allows the hormone to be released slowly in to the bloodstream. It is fitted into the womb by a trained nurse or doctor.
The IUS is over 99% effective. Less than 1 woman in 100 will get pregnant in a year.
How does it work?
- It makes the lining of the womb thinner so it is less likely to accept a fertilised egg
- It thickens the mucus from the neck of the womb making it difficult for sperm to move through it and reach an egg
- In some women it stops the ovaries producing an egg, but most women who use an IUS ovulate
- It works for 5 years
- You don’t have to think about contraception for as long as it is working
- It doesn’t interrupt sex
- Your periods usually become lighter and shorter, and sometime less painful. An IUD can be used if you have heavy, painful periods.
- Your normal fertility returns quickly when the IUS is removed
- It is not affected by other medicines
- There may be irregular bleeding for the first 3 months or so. This should then settle down
- Sometimes there are temporary side effects such as, headaches, spotty skin and breast tenderness. These usually go away after a few months
- Some women develop cysts on their ovaries in the first few months. These are not dangerous, and do not usually need to be treated. They will often disappear without treatment. Some women however, do experience some pelvic pain.
- You may be advised to have a check for any possible existing infection before an IUS is fitted. This will reduce the chances of an infection after insertion
- IUS’s are very effective at stopping pregnancy but they will give no protection against a sexually transmitted (STI), so you may need to use a condom as well.
- The IUS can be pushed out of the womb (expelled) or it can move (displacement). This is more likely to happen soon after it has been put in and you may not know it has happened. This is why your nurse or doctor will teach you how to check your IUS threads every month. This will not be brought on by anything that you have done, so continue your own routine eg gym, sport and exercise as normal.
- It is not common, but there is the risk that an IUS might go through (perforate) your womb when it is put in. This risk is very low when fitted by an experienced doctor or nurse.
Can anyone use an IUS?
Most women who want to use an IUS can do so, including women who have never been pregnant and women who are HIV positive. Your doctor or nurse will need to ask about medical history to check if an IUS is suitable for you, Some of the conditions which may mean you should not use an IUS are:
- If you think that you might already be pregnant
If you have now or in the past
- Cancer of the womb, ovary or breast
- Active liver disease
- Unexplained bleeding from the vagina (for example between periods and after sex)
- A heart attack, stroke (severe arterial disease) or thrombosis (blood clots)
- An untreated sexually transmitted infection or pelvic infection
- Problems with your womb or cervix
Where can I get an IUS?
You can go to the CaSH service or your own GP. Some GP’s will fit IUSs but not all. All treatment is confidential and free.
How is an IUS put in?
Fitting an IUS takes about 15 – 20 minutes. Some women find it uncomfortable and you may wish to take a painkiller. Your doctor or nurse will talk to you about that beforehand. You may get a period-type pain and some light bleeding for a few days after the IUS is fitted, painkillers can help with this.
How will I know that the IUS is still in place?
An IUS has two threads attached to the end that hangs a little way down from the womb into the top part of the vagina. The doctor or nurse will teach you to feel for the threads to make sure the IUS is still in place. You should do this at regular intervals.
Is it safe to use tampons if I have an IUS fitted?
Yes, you can use either tampons or towels during your periods.
How often do I need to see a doctor or nurse?
You should have your IUS checked three to six weeks after it is put in. The IUS can stay in for 5 years, during which time if you have any problems you can go and see your doctor or nurse at any time.
Will an IUS affect my periods?
Yes, at first there is usually irregular or longer bleeding. Most women find that after three months, their periods become lighter than usual. They may continue to be irregular and many women find that their periods stop altogether. If this happens to you, do not worry as it is perfectly healthy. When the IUS is taken out your periods will return to how they were before it was put in.
When can an IUS be put in?
An IUS is usually put in four weeks after a vaginal or caesarean birth and can be used while you are breastfeeding.
An IUS can be put in immediately after a termination of pregnancy or miscarriage if you were pregnant for less than 24 weeks.
If you have a medical termination of pregnancy (using pills) an IUS should be fitted in the first two days following, otherwise you will need to wait four weeks.
When can it be removed?
A trained doctor or nurse can take out the IUS at any time. If you are going to have another IUS put in, and you don’t want to become pregnant, use extra contraception, such as condoms, for seven days before IUS removal.
The IUS will give you no protection against sexually transmitted infections, we therefore recommend the use of condoms as well.