What is the intrauterine system (IUS)?
The IUS is a small, plastic device, which sits inside the womb (uterus). There are two threads attached to it, which pass out through the neck of the womb (cervix) and lie in your vagina. These allow you to check it is still there and are used to remove it. It looks like an intrauterine contraceptive device (IUCD) - also known as the 'contraceptive coil' or copper IUCD. However, the IUS does not contain copper; it contains slow-release progesterone hormone. It is therefore called an intrauterine 'system' (IUS) and not an IUCD.
There are two types of IUS available in Canada. They are called Mirena® and Jaydess®. They are T-shaped (the two side arms fold flat for insertion and fold up for removal) and about the length of a matchstick. The inside of the womb itself is only a little longer than a matchstick, so the IUS fits neatly inside. A trained doctor or nurse can place the IUS quite easily into a woman’s womb. Mirena® and Jaydess® are very similar but Jaydess® is smaller and has a lower dose of hormone loaded on it. This is why it is only effective for three years.
How does the IUS work as a contraceptive?
It works differently to the copper intrauterine contraceptive device (IUCD) because instead of copper it contains a progesterone hormone. The hormone thickens the mucus in the neck of the womb (cervix). This forms a plug, which stops sperm getting through to the womb (uterus) to fertilize an egg. The hormone also makes the lining of your womb much thinner which makes your periods much lighter (they may disappear altogether!). In some women the IUS suppresses ovulation, so that it happens less often or not at all. However, this is usually not the case, even if your periods are absent when using the IUS.
How effective is the IUS for contraception?
The IUS is very effective. Around 2 women in 1,000 using the IUS will become pregnant each year. Compare this to other methods in the attached chart and you will see just how effective the IUS is! Women not using contraception have a pregnancy rate of 800/1000!
What are the advantages of the IUS?
Advantages include: duration of effectiveness, reliability, lighter menstrual cycles and reversibility.
Once a Mirena® IUS is inserted you no longer need to use other contraception for five years. A Jaydess® IUS lasts for three years. So, unlike users of the oral contraceptive pill, ring or patch, you do not have to think about contraception every day! The IUS does not interfere with having sex (intercourse) or with sex drive (libido). Although it contains progesterone, the quantity of the hormone that gets into your general system is very low. It does not usually therefore cause the side effects, which can be seen with other progesterone-containing contraceptives (like Depo Provera).
Periods usually become lighter, less painful and can even stop altogether. After 12 months most users only have a light bleed for one to three days per month, and about 1 in 5 users of the Mirena® IUS have no bleeding at all.
Fertility returns as soon as the IUS is removed, although regular periods (menstruation) sometimes take a few months to return.
The Mirena® IUS does not have to be used as contraception. It can also be used as a treatment for heavy periods, endometriosis and fibroids. Jaydess® IUS is not suitable to treat these conditions.
What are the disadvantages of the IUS?
Although the majority of women with an IUS have no problems, the following may occasionally occur:
Irregular bleeding
You may have irregular bleeding for the first three to six months after IUS insertion. Your menstrual cycles may be slightly longer than usual or even a bit heavier for a while. You may experience spotting or light bleeding between your periods, which can be a nuisance. This usually settles down so we encourage you to try and be patient! The reward is often 4 and half years of light cycles with great, reliable contraception!
Ectopic pregnancy
An ectopic pregnancy is a pregnancy developing outside the womb (uterus). This is uncommon in women with an IUS but if you develop one-sided tummy (abdominal) pain with bleeding you should discuss this with a doctor right away.
Expulsion
The IUS may come out without you noticing (expulsion). This happens to 1 woman in every 20. It usually happens in the first three months during your period. It is slightly more likely to happen if you have not had children. It is a good idea to check you can feel the threads of the IUS after your period. If you cannot feel them, you should use extra precautions such as a condom until your doctor has checked the IUS is still there.
Infection and perforation
The risks of having an IUS inserted include infection and perforation.
Infection tends to occur within the first 3 weeks of insertion. The risk is approximately 1 in 200. It is often associated with symptoms of persistent fever, pelvic pain and vaginal discharge.
Perforation can occur during the insertion and is when the IUS makes a small hole in the uterus. The IUS can protrude through the wall of the uterus and can escape into the pelvis. This happens in fewer than 2 in 1,000 women. Perforation can occasionally cause pain but often there is no pain. The main symptom is not being able to feel the strings of the IUS. You should tell your doctor or nurse if you can no longer feel the threads of your IUS. An ultrasound scan will be carried out. If ultrasound does not find the IUS, an X-ray will be ordered.
Hormonal side effects
Hormonal side effects are uncommon. The progesterone released by the IUS mainly stays around the womb and very little gets into the bloodstream. So side effects are less common than with the progesterone-only contraceptive pill and the contraceptive injection or implant.
If side effects do occur, they tend to develop in the first 3-6 months. They then tend to ease and go. Examples of possible side effects include:
¥ Mood swings.
¥ Reduced sex drive (libido).
¥ Fluid retention.
¥ Increase in acne.
¥ Breast discomfort.
¥ A slight increase in breast size - this can occur in the first few months but is usually temporary.
There is no evidence that women with an IUS put on weight.
Who cannot use the IUS?
We will discuss your medical history with you. Some illnesses may mean you cannot use progesterone-based contraceptives. These include recent breast cancer, some other cancers, very large fibroids or an infection, which has not been treated. The number of women who cannot have the IUS inserted is small.
How is the IUS fitted?
The IUS is usually fitted towards the end of a period but it can be fitted at any time in your cycle provided you are certain you are not pregnant. You will have a gentle vaginal exam to check the size and shape of your uterus. A speculum will be placed and your cervix will be cleaned. Your cervix will be grasped and a small instrument will be passed into your uterus to check the depth of the cavity. The IUS is then inserted using a small plastic insertion device.
The IUS insertion can be uncomfortable and some women can have crampy pain afterwards. These can be eased with medications like Tylenol or Advil (ibuprophen). Light vaginal bleeding may occur for a few weeks.
You will be taught how to feel the threads of the IUS so you can check it is in place. You can check the threads regularly if you wish.
Does the IUS work right away?
If the IUS is fitted within seven days after the start of a period, it is immediately effective as a contraceptive. If it is fitted after the seventh day then you need to use extra protection such as condoms for seven days.
Follow-up
We will want to check that there are no problems 4-8 weeks after fitting your IUS. It is best done after your next period. After this, there is no need for any routine check other than routine well woman care until it is time to remove the IUS. See us at any time if you have any problems or queries.
Most women have no problems and the IUS can remain in place for three or five years.
Changing the IUS and other tips
A trained doctor or nurse can remove the IUS at any time.
You can use sanitary pads or tampons for your menstrual periods with an IUS in place.
A pap smear can also be taken with an IUS in place. Sometimes, the smear result may show that there is an organism in the cervix; these are called actinomyces-like organisms. These are normally found and do not mean the IUS should be removed.
If you have had pelvic pain together with signs of infection, such as a temperature, your doctor may consider removing the IUS.
You should consult a doctor if any of the following occur:
¥ Prolonged tummy (abdominal) pain after an IUS is inserted.
¥ New vaginal discharge with or without pain.
¥ You suspect that the IUS has come out or is coming out. If you cannot feel the threads then use other contraception (such as condoms or not having have sex) until a doctor or nurse has checked you.
