Intrauterine Contraceptive Device - How it works and who can have it

How does the intrauterine contraceptive device work?

It works mainly by making it difficult for sperm to fertilise an egg. This is an effect of the copper in the device. It makes the mucus at the neck of the womb (cervix) and the womb lining itself hostile to sperm and eggs. This means that it prevents sperm getting in through the cervix, and from travelling through the womb (uterus). It also makes your womb lining much less likely to accept an egg.

The intrauterine contraceptive device (IUCD) does not cause an abortion (which occurs when a pregnancy is ended after the fertilised egg as planted in the wall of the womb).

How quickly does the intrauterine contraceptive device work?

Once the IUCD is in place it works immediately. However, when it is fitted there is a very small chance that your body will expel it again. If this happens it usually happens in the first 24-48 hours.

Is there anyone who should not have the intrauterine contraceptive device?

The IUCD is not generally considered the best choice of contraceptive for those who already have heavy, painful periods, as it is likely to make this worse. In this case you may be better to consider an intrauterine system (IUS), which is a similarly shaped device which contains progestogen rather than copper.

The IUCD should not be put in if you are pregnant, have unexplained vaginal bleeding or vaginal or pelvic infection, or if you are known to have an abnormally shaped womb. It is also not advisable if you have any form of cancer affecting the pelvis.

If you have previously become pregnant with an IUCD in your womb, you might wish to choose another method for the future.

Can the intrauterine contraceptive device be used when breast-feeding?

Yes, the IUCD can be used when breast-feeding.

Although breast-feeding alone can delay the return of your periods and does slightly reduce the chance of another pregnancy, it is not a reliable contraceptive and it is possible to become pregnant whilst breast-feeding even before you have a period.

Can the intrauterine contraceptive device be put in after miscarriage or termination?

The IUCD can be put in immediately after miscarriage or termination of pregnancy in most cases.

Can the intrauterine contraceptive device be put in after childbirth?

The IUCD can be inserted straight after caesarean section or vaginal delivery, after the placenta is delivered (and as long as your delivery is not complicated by heavy bleeding or infection).

For women who would like to use an effective contraceptive straight after childbirth, this can be extremely convenient, as insertion is unlikely to be uncomfortable. The IUCD is not recommended between 48 hours and four weeks after delivery.

Beyond four weeks after delivery, the IUCD can be inserted safely.

Can the intrauterine contraceptive device be used as emergency contraception?

The IUCD is a very effective form of emergency contraception which is effective for up to five days after you have had unprotected sex (intercourse). It prevents more than 9 out of 10 pregnancies which would otherwise have occurred. It can be left in place to provide ongoing contraception.

The IUCD is the most effective method of emergency contraception - but it is not available everywhere, not all doctors are able to fit it and there may not be emergency appointments available at just the right time. Therefore, if you need emergency contraception it is important to try to make arrangements for this as early as possible.

If you don't want to continue to use the IUCD as contraception it can be removed after you have had your next period.

If I have an intrauterine contraceptive device, what do I do when I want to try to get pregnant?

If you feel you would like to try for a baby, you will need to have the IUCD removed. Your fertility will return immediately and if your periods have been heavier than before they will usually return to normal after a couple of cycles. It is possible to get pregnant before you have your first period. This is because you produce an egg two weeks before a period occurs.

If you want to try for a baby, start pre-pregnancy care such as taking folic acid and stopping smoking. You can ask your doctor or nurse for further advice.

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Dr Mary Lowth
Peer Reviewer:
Dr Jacqueline Payne
Document ID:
4285 (v42)
Last Checked:
08 July 2017
Next Review:
07 July 2020

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.