The contraceptive coil comes in two different types: copper-based intrauterine devices (IUD) and hormonal intrauterine devices (sometimes known as IUS – intrauterine system). Both are essentially made of plastic, then either "coated" with copper or hormones.
Both methods of IUD contraception are inserted into the uterus to provide long-term and highly effective protection against pregnancy (above 99% effectiveness).
This protection lasts for 5-10 years.
They do not protect against sexually transmitted infections.
This IUD is a small T-shaped device that releases copper ions which kill sperm. The coil works by stopping sperm from getting to the ovaries and by stopping the fertilized egg from implanting in the uterus.
There are threads attached to the coil, which make it easy for you to check it is still in place.
The coil can be used for emergency contraception if inserted within 5 days after unprotected sex.
The copper coil works for about 10 years. You need to attend regular check-ups to make sure that the coil is still in place. Contraception with the coil is about 98-99% effective over a period of 5 years.
The biggest advantage of using a contraceptive coil is that you don't need to think about contraception every time you have sex.
Except a risk of heavier periods, copper IUD contraception doesn't usually cause side effects because it doesn't rely on hormones to prevent pregnancy.
Your doctor needs to implant the IUD. You'll need to go back to your doctor one month later, who will check whether the coil is still placed correctly. Regular follow-ups are necessary.
In terms of side effects, some women experience heavier and more painful periods with the copper-based contraceptive coil. This can be a problem if you are already prone to heavy and painful periods. If that applies to you, this type of contraception might not be right for you.
Other side effects are uncommon but include:
Your doctor will check for signs of infection in the 3-4 weeks after the contraceptive coil has been inserted.
Another (rare) risk is that the IUD comes out or slips out of its place – which is most likely to happen during the first 3 months. If this happens, you should see your doctor as soon as possible. You can also try to check the threads that come with it to see if it is in place.
For your own safety, you should never try to put the IUD back in place yourself. Always leave it to a healthcare professional to insert the contraceptive coil.
The physical appearance of the hormonal coil is fairly similar to that of copper-based ones. It is the same T-shaped plastic device, except that it is “coated” with hormones in this case.
The effect of these hormones is, rather than killing sperm, to make it very difficult for sperm to reach the ovaries. The coil also makes it less likely for a fertilised egg to successfully implant in the womb. In addition, the hormones can prevent the ovaries from releasing an egg.
The hormone coil also has threads attached to it (just like the copper-based coil), which makes it easy to remove and to check its position.
Hormonal intrauterine contraception is just as effective in preventing pregnancy as the copper-based version. Even though it “only” lasts about five years, it also makes periods much lighter and less painful after about 3-6 months.
This method can also be a treatment for heavy periods and endometriosis. It also reduces the risk of pelvic inflammatory diseases (PID).
Just like the copper coil, it can also be removed at any time, allowing for a swift return to fertility.
Side effects are more common with the hormonal coil than with the copper coil. However, they remain quite uncommon because the hormones mostly affect the uterus.
Side effects tend to appear in the first 3-6 months and improve over time. The coil tends to cause less side effects than the pill or any hormonal contraceptive which enters the bloodstream.
Side effects range from headaches to mood swings, worsening of pre-existing acne, breast tenderness, nausea and irregular bleeding (especially during the first 3-6 months).
As for the problem of the coil becoming dislodged and being pushed out of your body, it happens in 20% of cases (usually within the first three months). Risk factors that increase the chances of this happening are the same as for copper-based intrauterine contraception, e.g. women who have never been pregnant, tend to have heavy periods, are less than 20 years old and have already expelled an IUD before.
Your doctor may find that you are not suitable to use the hormonal contraceptive coil if you: