The intra uterine device (IUD) is a form of long-acting reversible contraception for women. This page explains how the IUD works and tells you how to use it.
What is an intra uterine device (IUD)?
An IUD is a small device that fits inside your womb.
You can’t feel it or tell it is there except by checking for the threads. Your partner should not be able to feel it and you can still use tampons.
The removal threads come out of your cervix and curl up inside the top of your vagina – they don’t hang outside.
There are two types of IUDs:
- Copper IUD - contains copper
- Hormone-releasing IUDs - the progestogen hormone is slowly released into your womb.
How does it work?
The main way an IUD works is by preventing fertilisation of the egg.
The copper or the hormone from the IUD stops the sperm moving through the womb towards the egg.
Occasionally an egg is fertilised. The IUD then stops the egg settling (implanting) into the womb.
How well does it work?
Copper and hormone IUDs are at least 99% effective in preventing pregnancy - only one woman out of 100 will get pregnant each year.
What will I notice?
With a copper IUD, spotting, light bleeding, heavier or prolonged bleeding and pain with bleeding are common in the first three to six months of use. This usually improves with time.
With a hormone IUD (Mirena or Jaydess), for the first three to six months your periods may be lighter but longer and you may have some bleeding or spotting in between your periods.
After this, many women have lighter periods and some have no bleeding at all. This is safe for your body.
Will I become pregnant after the IUD is removed?
Your natural fertility will return as soon as you have the IUD removed.
If you get pregnant with an IUD in place, and decide to continue with your pregnancy, the chance of having an abnormal baby is not increased. You will need to have the IUD removed.
What are the advantages of having an IUD?
- Long acting - can stay in place for three or more years.
- Reversible - possible to get pregnant as soon as the IUD is removed.
- Very effective – at least 99%.
- Can be easily removed (by any doctor or Family Planning nurse) if you don’t like it or want to get pregnant.
- Does not affect breastfeeding.
- Does not interfere with sexual intercourse.
- No-one else needs to know you are using it.
- No evidence of an increased risk of cancer.
- Copper IUDs do not contain any hormones.
- Copper IUDs can also be used to prevent pregnancy after unprotected sexual intercourse (emergency contraception).
- Hormone IUDs release a very small dose of hormone and most women have no side effects from this.
- Mirena reduces period bleeding and pain so most women will have light bleeding or no periods at all.
What are the disadvantages of having an IUD?
- You have to have the IUD inserted. This is usually a simple, safe procedure carried out by a doctor or nurse who is experienced at inserting IUDs. It takes about five to 10 minutes.
- Most women have some period-like cramping. Some women feel pain and occasionally feel faint when the IUD is put in or taken out.
There are some risks from having an IUD put in:
- there may be a small chance of infection (about 1%) when an IUD is put in.
- there is a very small risk of damage or perforation of the womb (about 1 in 1,000).
- you may get pregnant with an IUD in place but this is rare.
- any pregnancy can be ectopic (in the tubes). This risk is less than in women not using any contraception/ārai hapū.
- a copper IUD may cause more bleeding and cramping during periods.
- the copper can very rarely cause an allergic reaction.
- Hormone IUDs may initially cause irregular, light bleeding for more days than usual. There is no evidence that hormone IUDs cause acne, headaches, breast tenderness, nausea, mood changes, loss of libido or weight gain.
- The IUD can occasionally come out by itself (about 5%). You can check the strings are still in place after each period or at the beginning of each month.
Who can use it?
Most women are able to use an IUD including young women and women who have not had children.
Hormone IUDs are particularly suitable for women with heavy periods.
Who should not use it?
Women who have symptoms of infection should have treatment before an IUD is inserted.
The copper IUD is not suitable for women with heavy or painful periods as it may make them more heavy or painful.
What should I do before I get an IUD?
Talk to a nurse or doctor at Family Planning about all the possible benefits, risks and side effects of an IUD for you. They may recommend you have tests for STIs.
Can an IUD be inserted anytime?
An IUD can be inserted any time it is clear you are not already pregnant, ideally:
- during or just after a menstrual period
- six weeks after your baby is born
- at the time of a surgical abortion
- as emergency contraception after unprotected intercourse (Copper IUD).
What should I know before my appointment?
Eat something before your appointment so you are less likely to feel faint.
You may want to take pain relief tablets before the appointment – ask the doctor or nurse which tablets and when to take them.
Most people go straight back to their usual routine after an IUD is put in. In case you feel faint or have cramps after the procedure, you may want to have someone available to drive you home, and have the option of resting for a few hours.
Allow an hour to be in the clinic.
Read our IUD instructions if you are having an IUD inserted so you are well prepared.
How do I look after my IUD?
You will be given more details when your IUD is put in. You should return to the clinic for a check-up about six weeks after your IUD is put in, to make sure it is still in the correct place.
How do I look after myself with an IUD?
Check your IUD threads after each period or at the beginning of each calendar month. See a doctor if you have unusual pain, bleeding or discharge, you think your IUD is coming out or has come out (you may need emergency contraception) or you think you may be pregnant.
If you are pregnant with an IUD in place you need to have a check that the pregnancy is not ectopic (in the tubes). If you decide to continue with the pregnancy the IUD needs to be removed to decrease the risk of infection and miscarriage.
Will an IUD protect me from sexually transmissible infections (STIs)?
No. You need to use condoms (and lubricant) as well to protect against STIs. If there is a chance you may have an STI, have a check-up.
How is the IUD removed?
Your doctor or nurse can remove an IUD by inserting a speculum and pulling the threads. This may be uncomfortable for a few seconds.
If you want to become pregnant the IUD can be removed at any time of your cycle. If you don’t want to become pregnant we need to be sure there is no chance of an unplanned pregnancy from sexual intercourse during the last week.
It is better to start alternative contraception before removing the IUD or do not have any sexual intercourse for at least seven days before the removal.
Family Planning has clinics located throughout New Zealand. Use the clinic finder to find your nearest clinic.