Intrauterine contraceptive devices (IUDs)
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An intrauterine contraceptive device (IUD) is a small device which is fitted inside the uterus, where it can remain for lengthy periods to prevent pregnancy.
What is an IUD?
- Hormonal IUD
- Mirena® is the brand name for the IUD which releases a progestogen (a hormone similar to the hormone progesterone, which is naturally produced by the female body). It is T-shaped, made of plastic and steadily releases small amounts of the progestogen directly into the uterus.
- Copper IUD
- Copper IUDs are made of plastic and copper. There are 2 types of copper IUDs currently available in Australia.
IUDs are inserted into the uterus. Once inserted they are not felt by the woman or her partner. All IUDs available in Australia have fine nylon threads attached to the lower end of them so that when fitted, the threads extend through the cervix (neck of the womb) into the upper vagina. These threads allow the woman to check that the IUD is still in place and allow for easy removal of the device by a doctor.
How do IUDs work?
IUDs work by:
- preventing sperm from moving through the uterus and fertilising ova (eggs)
- changing the lining of the uterus making it unsuitable for a pregnancy
- the hormone in Mirena® thickens the mucus of the cervix, preventing sperm entering the uterus
How effective is an IUD?
Both types of IUDs are highly effective.
The copper IUDs are at least 99% effective. This means that, on average, if 100 women use an IUD for 1 year, it is possible that 1 of them could become pregnant.
Mirena® is approximately 99.9% effective. This means that, on average, if 1000 women use Mirena® for 1 year, it is possible that 1 of them could become pregnant.
What are the advantages of using an IUD as a method of contraception?
- highly effective
- long acting
- reversible with rapid return to usual fertility when removed
- relatively inexpensive
What are the main differences between copper and hormonal IUDs?
While there are many similarities, there are some differences between copper and hormonal IUDs. Making a choice about which IUD is most suitable for you will be based on your own preferences, requirements and medical issues.
Lifespan of different IUDs
- Mirena is effective in preventing pregnancy for 5 years
- Multiload® and Load Cu 375® are effective for 5 years
- TT 380 ® Standard is effective for 10 years. This is sometimes called a copper T
Effect on bleeding patterns
- during the first 3-5 months after insertion unpredictable, irregular light bleeding is common
- after about 5 months nearly all women will experience light or no bleeding
- after 12 months at least 20% of women will have no bleeding at all
- Mirena can be used to treat excessively heavy menstrual bleeding. Heavy menstrual bleeding should be investigated by a doctor prior to insertion
- reduces period pain in many women
- following insertion, there may be a few weeks of irregular spot bleeding
- the frequency of periods will be the same as that experienced prior to insertion but blood loss may increase in amount and number of days of bleeding
- some women may experience more painful periods
Hormonal side effects
- only a very small amount of progestogen passes into the bloodstream and hormonal side effects therefore are extremely rare
- if they do occur they are generally mild and often improve with time
- research has found no difference in the rate of symptoms, such as headache, acne, mood change, weight gain, between users of copper IUDs and those using hormonal IUDs
- there are no hormonal side effects as copper IUDs do not release hormones
- the hormonal IUD is a prescription item and its cost is treated like other prescriptions that are subsidised by the Australian government
- the cost of these devices is not subsidised and is more expensive to purchase than Mirena
What are the possible risks of using an IUD?
Possible risks associated with the insertion procedure include:
- Abdominal pain
Following insertion, some women notice abdominal cramping pain for up to a few weeks. This appears to be more common in women who have not had children.
This is a rare but serious complication where the IUD device passes through the wall of the uterus into the pelvic area, usually at the time of, or shortly after insertion. This may occur in about 1 per 400 insertions. This requires surgery under a general anaesthetic to remove the IUD. Some studies have found that women who have recently given birth may have an increased risk of this complication, however all women may be at risk of this rare event occurring.
Sometimes the IUD device may be partially or completely pushed out of the uterus. It occurs in about 5 per 100 insertions and is most common in the months following insertion. It is important to regularly check for the threads, to detect if this has occurred, as the IUD won't work effectively if not fully within the uterus.
- Pelvic inflammatory disease (PID)
This is a rare complication of IUD insertion, most likely to occur in the first few weeks following the insertion procedure. It occurs in approximately 1 per 500 insertions. PID may in some cases lead to infertility.
Possible risks associated with ongoing use of an IUD:
If a pregnancy occurs in the uterus there is an increased risk of miscarriage. If the IUD is then left in place, there is an increased risk of miscarriage with infection in later stages of pregnancy or premature birth.
- Ectopic pregnancy
If a pregnancy does occur with an IUD in place there is a small chance the pregnancy will develop in the Fallopian tube.
However, because the IUD prevents most pregnancies, it is an uncommon complication and less common than amongst women who are not using any contraception. Ectopic pregnancy is a serious condition and can lead to reduced fertility.
To reduce complications, in the rare event of a pregnancy occurring with an IUD in place, it is important to see a doctor as soon as possible if you have any reason to suspect you are pregnant, eg, if there is a change in your usual bleeding pattern, if a period is missed, is lighter than usual or you have unusual abdominal or pelvic pain.
Is an IUD suitable for all women?
Most women can safely use an IUD.
Your doctor will review the suitability of the method with you prior to insertion.
In assessing your suitability, consideration is given to a number of important factors:
- current menstrual and bleeding patterns
- unexplained vaginal bleeding (this should be investigated before using an IUD)
- a recent history of a sexually transmitted infection or PID
- uterine or cervical abnormalities
- any history of breast, cervical or uterine cancer
The doctor will also review:
- previous pregnancies
- whether you need to have a Pap smear and other tests for infection prior to insertion
- any allergies including copper allergy
- the timing of insertion and pain relief needs for the insertion procedure
If your general health changes, the suitability of this method should be reassessed.
What do I need to know about having an IUD insertion?
Prior to insertion, an assessment of your medical history and suitability for this method will happen. This assessment enables you to ask any questions you may have and be certain that it is the most suitable method for you. A pelvic examination will be performed. A Pap smear, if due, and other tests to check for infection, may also be required.
Insertion of an IUD involves a procedure. Some women find insertion quite uncomfortable. This can be managed with the use of local anaesthetic into the cervix but occasionally requires a sedative or general anaesthetic.
The device should be inserted by a medical practitioner trained in the procedure.
What do I need to know about the ongoing use of an IUD?
You will be given details of follow up at the time of the insertion. Generally, you are asked to attend for a follow up visit after insertion and/or any time concerns exist.
You should contact your doctor if:
- you feel you may be pregnant If using a copper IUD you should contact a doctor if you miss a period
- you experience pelvic pain or tenderness, fever or chills, offensive discharge or deep pain with intercourse
- you cannot feel the string or feel the string has lengthened
- you (or your partner) can feel the hard stem of the IUD
The IUD needs to be replaced with a new device every 5 or 10 years depending on which device is inserted.
However, if you have a copper IUD inserted after the age of 40 or a hormonal IUD inserted after the age of 45, this expiry date can often be extended and the same device left in for a longer period of time. This is because you have a lower risk of falling pregnant in your late 40s and 50s. Please discuss further with your practitioner.
It is important to keep a record of the date that replacement is due and to arrange for replacement no later than this date.
The IUD can easily be removed at any time. As fertility can return immediately after removal, it is important to consider alternative methods of contraception before the IUD is removed, if trying to avoid pregnancy.
Can the IUD be used as emergency contraception?
In some circumstances a copper IUD can be inserted up to 5 days after unprotected sex to prevent pregnancy occurring. It can be left in place to provide ongoing contraception or removed after a normal period.
Where is the IUD available?
The IUD is available from Family Planning Queensland (FPQ) clinics, gynaecologists, as well as some general practitioners (GPs).
To make sure you are protected against both pregnancy and STIs, use an IUD plus a condom, for best protection.
Phone 07 3250 0240
Family Planning Queensland (FPQ) has taken every care to ensure that the information contained in this publication is accurate and up-to-date at the time of being published. As information and knowledge is constantly changing, readers are strongly advised to confirm that the information complies with present research, legislation and policy guidelines. FPQ accepts no responsibility for difficulties that may arise as a result of an individual acting on the advice and recommendations it contains.
© Family Planning Queensland
Version 3 / June 2010
P: 06/2010 10m
Funded with assistance by Queensland Health