Intrauterine System

What is it?

• A small, flexible piece of soft plastic that fits inside the womb.
• It is easily inserted by a trained health care professional.
• It releases a hormone progestogen into the womb.

How does it work?

• The hormone thickens the mucus at the entrance to the womb preventing sperm getting through and thins the lining of your womb preventing implantation of a fertilised egg. It may also stop ovulation (eggs being released from the ovaries) in somewomen.

What’s great about it?

• Extremely effective (>99%). Less than 1 in 500 women will become pregnant using the device.
• Contraception lasts for 3-5 years unless you want it removed earlier.
• Periods usually become lighter, shorter and sometimes less painful.
• Intrauterine system users, by one year, commonly do not experience any bleeding.
• Can be used by women who have never had a baby.
• Fertility returns as soon as it is removed.
• There will be no need to take pills, interrupt sex or requirement to attend clinic regularly after insertion.
• Is not affected by other medications.

What’s not so great about it?

• No protection against sexually transmitted infections (STIs) - condoms advised.
• Insertion can be slightly uncomfortable. Local anaesthetic is offered.
• Can cause unpredictable bleeding pattern for the first three months, but after this time bleeding becomes infrequent and irregular, or stops altogether.
• Can become displaced or fall out (expulsion) but this is uncommon (5 in 100) and you can do checks yourself to make sure it’s in place.
• Small risk of pelvic infection for up to 3 weeks after insertion. This risk is reduced by having a sexual health screen prior to the fitting.
• Very small risk of perforating the womb or cervix (1 in 500 risk).

Where can I get it?

• Sexual Health services. A preliminary appointment is usually required before fitting this method to discuss the method fully, screen for infections and schedule a fitting date.
• Family planning clinics
• Some GP practices