Mirena Poster

Dr Diana Mansour answers your questions

  • How do long-acting reversible contraceptives (LARC) compare to other methods in terms of their contraceptive protection?
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Effectiveness (in preventing pregnancy)

Each type of long-acting reversible contraceptive (LARC) is effective at preventing pregnancy and as a consequence pregnancy rates are very low. However, in rare cases you may become pregnant. There have been many long-term studies to assess the effectiveness of each contraceptive method.

Intrauterine system (IUS)

The intrauterine system can provide you with contraceptive protection for up to 5 years. Pregnancy rates with this type of contraceptive are very low. Only around 2 per thousand women may become pregnant in the first year1. By using the intrauterine system, which is permanently in place, no pregnancies occur due to problems remembering to use or take a contraceptive.

Women who rely on their partner using condoms can typically experience a pregnancy rate of as high as 180 per thousand women per year (only 20 per thousand if used perfectly)1.

As with other long-acting reversible contraceptives (LARC), the intrauterine system offers the advantage of a contraceptive that you don’t have to think about and which doesn’t spoil the spontaneity of sex.

You should tell your healthcare professional if you are taking or have recently taken any other medicines, including medicines obtained without a prescription2. Since the mechanism of action of the intrauterine system is mainly local, taking other medications is, however, not believed to have major importance for the contraceptive effectiveness of the intrauterine system2.

Note: The intrauterine system (IUS) is also known as the ‘hormonal coil’.

Intrauterine device (IUD)

A copper intrauterine device will provide you with effective contraception for up to 5 and 10 years,3,4 depending on the model used. Pregnancy rates with this type of contraceptive are very low. Between 6 (perfect use) and 8 (typical use) women per thousand become accidentally pregnant during the first year of using the intrauterine device1. By using the intrauterine device, which is permanently in place, no pregnancies occur due to problems remembering to use a contraceptive.

Women who rely on their partner using condoms can typically experience a pregnancy rate as high as 180 per thousand women per year (only 20 per thousand if used perfectly)1. As with other long-acting reversible contraceptives (LARC), the intrauterine device offers the advantage of a contraceptive that you don’t have to think about and which doesn’t stop the spontaneity of sex.

Note: The intrauterine device (IUD) is also known as ‘the coil’ or copper IUD.

Contraceptive implant

The implant will provide you with effective contraception for up to 3 years although if you are overweight the doctor may advise you to replace the implant earlier5. Pregnancy rates with this type of contraceptive are very low. Less than one per thousand women will get pregnant during the first year of using the implant1. By using the implant, which is permanently in place, no pregnancies occur due to problems remembering to use a contraceptive.

Women who rely on their partner to use condoms can typically experience a pregnancy rate of as high as 180 per thousand women per year (only 20 per thousand if used perfectly)1.

As with other long-acting reversible contraceptives (LARC), the implant system offers the advantage of a contraceptive that you don’t have to think about and which doesn’t stop the spontaneity of sex.

The contraceptive efficacy of the contraceptive implant may be reduced if you use other medications. These include medicines used for the treatment of epilepsy (e.g. primidone, phenytoin, barbiturates, carbamazepine, oxcarbazepine, topiramate, felbamate), tuberculosis (e.g. rifampicin), HIV infections (e.g. ritonavir, nelfinavir, nevirapine), other infectious diseases (e.g. griseofulvin), depressive moods (the herbal remedy St. John’s wort)5. The contraceptive implant may also interfere with the working of other medicines; e.g. increase the activity of ciclosporin and decrease the effect of lamotrigine5.

You should always tell your healthcare professional which medicines or herbal products you are already using5. They can tell you if you need to take additional non-hormonal contraceptive precautions and if so, for how long, since the interaction may last up to four weeks after you stop using the contraceptive implant5. They may also advise that the contraceptive implant is removed5. If you want to use herbal products containing St. John’s wort while you are already using a contraceptive implant, you should consult your healthcare professional first5.

3-monthly contraceptive injection

The 3-monthly contraceptive injection is highly effective in preventing pregnancy. Pregnancy rates with this type of contraceptive are very low. Within the first year of use the pregnancy rate is between 2 (perfect use) and 60 (typical use) per thousand women1.

By using the 3-monthly contraceptive injection, no pregnancies can occur due to problems remembering to use the contraceptive.

Women who rely on their partner to use condoms can typically experience a pregnancy rate of as high as 180 per thousand women per year (only 20 per thousand if used perfectly)1.

As with other long-acting reversible contraceptives (LARC), the injection system offers the advantage of a contraceptive that you don’t have to think about and which doesn’t stop the spontaneity of sex.

Tell your doctor if you are taking aminoglutethimide as this may affect the way your 3-monthly contraceptive injection works. Also tell your doctor if you are taking any other medicines. This includes ’over the counter’ medicines from the pharmacy6.