The IUS or Mirena is a small plastic T-shaped device. It is placed inside the womb and slowly releases progesterone. There are two threads attached to the mirena which pass through the entrance of your womb into your vagina. These allow you to check that the coil is in place and allow easy removal. Your partner doesn’t usually feel them during intercourse, and they don’t hang outside your body.

What is the Mirena Used for?

The Mirena is a very reliable and common form of contraception.

It is the most effective treatment to reduce heavy periods – reducing bleeding by approximately 90%.

It can be used to provide the progesterone component of HRT which protects the lining of your womb. Side effects of progesterone given by the Mirena are much less than those experienced by patients taking oral progesterone.

How is it fitted?

The Mirena coil is easily fitted in our practice. The process is very much like having a smear but takes a little longer. We advise that you take paracetamol an hour before the procedure to reduce any period type pains that you might experience on insertion. We must ensure that you are not pregnant before fitting the Mirena so you must not have unprotected sex between your last period and your fitting appointment.  Once fitted the Mirena can be left in place for 5 years. If you wish to have a coil fitted you need to book a phone consultation with a coil fitter who will discuss the process and then book you a face to face appointment for the fitting.

What are the risks?

There are a few very small risks associated with fitting the coil.

• Occasionally we are unable to fit the coil in the clinic. We would then discuss alternative options with you.
• Rarely, (approx. 1 in 1000) on insertion, the coil might pass through the womb wall and then we would need to refer you to hospital for an operation to remove the coil.
• Sometimes the coil falls out of your womb (expulsion). This happens in about 1 in 20 women and we ask you to check that your coil is in place each month by feeling for the threads.
• There is a slight increased risk of infection, so where necessary we will ask you to do a vaginal swab to reduce that risk.
• The Mirena is a very effective method of contraception but if you did get pregnant, there is a chance that the pregnancy would implant outside your uterus. This is known as an ectopic pregnancy and would require referral to the hospital for management.

Are there any side effects?

The Mirena can cause some irregular bleeding during the first six months after fitting. This usually settles and most people don't have any further bleeding. 

You might experience some progesterone side effects such as breast tenderness, headaches, and symptoms similar to premenstrual syndrome, but these normally settle within the first few months.

What about follow-up?

When you leave the clinic you can return to your normal activity. If you are using the Mirena for contraception it will be effective after seven days and you will need to use extra protection to prevent pregnancy in that time. You may experience slight bleeding and period like pains for which you can take paracetamol or ibuprofen.

Most people don’t need any follow up but if you experience any problems or would like a follow up you can book through the reception team.