•  It thickens the mucus in your cervix so it helps to stop sperm reaching an egg.
•  In some women it stops the ovaries releasing an egg (ovulation), but most women who use an IUS still ovulate.
•  It makes the lining of the womb thinner so implantation cannot happen.

The IUS is very safe – less than 1 in 100 women will get pregnant during the time the coil is in place.

•  It works as soon as it is put in.
•  It lasts for 3 – 5 years depending on which type is fitted.
•  After you have used the IUS for about 3 months your periods usually become lighter and shorter. The Mirena IUS in particular can be useful if you normally have heavy painful periods.
• Both Mirena and Jaydess usually reduce or eliminate period pain.

• Most women have slight bleeding between periods for the first 3 months or so.
• Temporary side effects such as headaches, acne and breast tenderness are possible.
• These usually settle down within a few weeks.
• Infection may be introduced into your womb when the coil is being put in.
• The womb can push the IUS out. This is rare but if it does occur it is most likely to happen within a few weeks of it being put in.
• The IUS may go through the wall of the womb as it is being inserted. This is very unlikely when it is fitted by an experienced doctor.

The device must be put in by a specially trained doctor. The device is fitted sometime during the first 7 days of your cycle. This is because this is the time when the neck of your womb (cervix) is softest and so the device is easiest to fit. You may also be asked to insert 2 tablets (containing a hormone called misoprostol) into your vagina 3 hours before the device is fitted because these will also help soften your cervix. Fitting an IUS can be uncomfortable so it is a good idea to take a painkiller beforehand. You may get a period-type pain for a few days afterwards. Talk to the doctor about taking pain relief to help with this.

During insertion, the threads of the coil are normally cut so that about an 1 – 2 inches of thread is visible at your cervix.

You should come back for a check-up about 6 weeks after the IUS is fitted when we can check that the threads are still visible which means that the device is in place. After the six weeks check, if everything is normal then you do not need further check ups. However if you get any unusual bleeding please make an appointment to see a one of our doctors. In some women who have the Mirena fitted periods may stop completely. This is normal and is not a cause for concern.

A trained doctor can take out the IUS at any time. If you are planning to have the device taken out, you should ether abstain from sex or use a condom for the week before the coil is taken out. This is because sperm can live for several days and there is a possibility of you getting pregnant if the coil is taken out within a few days of sexual intercourse.

It rare with the hormonal coils. If you get pregnant an ultrasound scan can determine where the pregnancy has implanted. If the device is below the pregnancy and the coil threads are easily seen then a doctor will remove the device. However if the threads are not visible then it is better just to leave the IUS in place.
There is an increased risk of ectopic pregnancy* if you get pregnant with a coil in place. So if you have any unusual bleeding and particularly if a period is late please take a pregnancy test. If you have pelvic pain and or bleeding and a positive pregnancy test you should go to your nearest maternity hospital or A/E department.
If the coil remains in place throughout a pregnancy there is no increased risk that it will cause a baby to have any problems after delivery.

*An ectopic pregnancy is where the pregnancy implants outside of the uterine cavity – usually in a fallopian tube. It can cause severe pain and bleeding and needs urgent medical care.

The device has no effect on your ovarian function so you would return to normal fertility when the device is removed.