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Intrauterine system (IUS)

What is it?

The IUS is a long-acting reversible contraception (LARC) and contains the hormone progestogen. It is a small “T” shaped device, roughly the size of a matchstick, made from plastic that is inserted into the womb. The IUS is fitted by a doctor or nurse and is effective for up to 3 or 5 years depending on the type. It has two soft threads at one end that hang through the opening at the entrance of your womb (cervix) into the top of your vagina.

Once fitted the IUS should be checked by your doctor or nurse six weeks after insertion. If you have any problems you can go back any time.

This method does not protect you against sexually transmitted infections (STIs), so you may need to use a condom as well to help protect you against most STIs.

Intrauterine system (IUS) How does it work?

The IUS works by:

  • Thickening the mucus of the cervix to act as a barrier to sperm
  • Stopping a fertilised egg settling by keeping the lining of the womb thin
  • Sometimes stopping the ovaries releasing an egg

Intrauterine system (IUS) How effective is it?

The IUS is over 99% effective.

What are the benefits?

  • No need to remember to take a pill every day
  • You are protected from pregnancy for up to 3 or 5 years depending on the type of IUS
  • Doesn't interrupt sex
  • May be suitable for breastfeeding women
  • Hormones do not have to go through the stomach so protection is not affected by sickness or diarrhoea
  • Your periods may become lighter
  • Fertility returns quickly when removed

Intrauterine system (IUS)Women may not be able to/may not want to use it if they:

  • Don't want any changes to their periods
  • Don't want to have a small procedure to fit and remove the device

Women should not use it if they:

  • Might be pregnant
  • Have or have had pelvic inflammatory disease
  • Have or have had any type of cancer or suspected cancer including breast cancer
  • Have had problems with their womb or cervix
  • Have active liver disease
  • Have Trophoblastic disease (a doctor will have told you if you have this)
  • Have a sensitivity to any of the ingredients in the IUS
  • Have unexplained bleeding from the vagina

Intrauterine system (IUS) Possible side-effects?

As with all medicines side effects can occur but not all women will experience side-effects. Side effects may include:

  • Breast tenderness, acne, headaches
  • Risk of infection after fitting in the first 20 days
  • Irregular bleeding/spotting
  • There is a risk that the IUS might go through (perforate) your womb or cervix when it is put in. This is rare when fitted by an experienced doctor or nurse. This may cause severe pain, continued bleeding or a temperature after the IUS is fitted
  • Lower abdominal pain or you may experience painful or difficult sex
  • The IUS can be pushed out of your womb (expulsion) or it can move. This is why your doctor or nurse advises you to check the threads every month
  • Increase in the risk of developing ovarian cysts

Intrauterine system (IUS) What if......?

I want to become pregnant?

A trained doctor or nurse can remove the IUS at any time. Ideally you should wait for one period before trying to get pregnant. Waiting means the pregnancy can be dated more accurately, and you can seek some pre-pregnancy advice from your healthcare professional.

What if I want to check if my IUS is still in place?

After each period you can feel for the two thin threads attached to the lower end of the IUS. Do not pull these threads. If you cannot feel the threads contact your doctor or nurse.

Remember: Contact your doctor or nurse if you have any concerns or are worried / unsure about anything to do with your contraception.

Have you decided which might be the right contraception for you? If not check out the other choices, if you have, jump to Step3: How do I change?

© 2015 Merck Sharp & Dohme Ltd. All rights reserved.

Job code: WOMN-1160817-0000

Date of preparation: September 2015

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