Micronor contraceptive tablets are a type of hormonal contraceptive commonly known as the 'mini pill' or progestogen-only pill (POP). They contain the active ingredient norethisterone, which is a synthetic progestogen, similar to the natural progestogens produced by the body.
Micronor contraceptive tablets prevent pregnancy in three ways.
Firstly, they affect the natural mucus at the neck of the womb (cervix). Norethisterone increases the thickness of this mucus, making it more difficult for sperm to cross from the vagina into the womb. By preventing sperm entering the womb, successful fertilisation of an egg, leading to pregnancy, is less likely.
Norethisterone also changes the quality of the womb lining (endometrium). The changes prevent any eggs that have been fertilised from successfully implanting onto the wall of the womb.
Lastly, norethisterone may prevent the release of an egg from the ovaries, however this may not occur in all women who take the mini-pill.
Micronor contraceptive tablets should be taken every day on a continuous basis, ie you take the packs back to back without a break, including when you are having a period. (This is unlike the combined pill, which is usually taken every day for three weeks, followed by a pill-free week.)
Micronor contraceptive tablets must be taken continuously, at the same time every day, for them to be effective at preventing pregnancy. If you are more than three hours late taking your pill, you will not be protected against pregnancy. If this happens, you should use an extra barrier method of contraception, eg condoms, for the next two days, while continuing with your normal pill taking.
Ideally, you should start taking this pill on day one of your menstrual cycle (the first day of your period). This will protect you from pregnancy immediately and you won't need to use any additional methods of contraception. If necessary, you can also start taking it up to day five of your cycle without needing to use additional contraception when you start. However, if you have a short menstrual cycle (with your period coming every 23 days or less), starting as late as the fifth day of your cycle may not provide you with immediate contraceptive protection. You should talk to your doctor or nurse about this and whether you need to use an additional contraceptive method for the first two days.
You can also start taking this pill at any other time in your cycle if your doctor is reasonably sure that you are not pregnant. If you start taking this pill at any other time in your cycle, you will need to use additional contraception, eg condoms for the first two days of pill taking.
If you are starting this pill after giving birth, you are protected against pregnancy immediately and do not need to use extra contraception if you start taking it on day 21 after giving birth. (You can start before day 21, but this increases the risk of breakthrough bleeding and is unnecessary.) If you start taking it later than 21 days after giving birth, you should use extra contraception for the first two days.
If you are starting this pill immediately after a miscarriage or abortion at under 24 weeks, you will protected against pregnancy immediately. If you start taking it more than seven days after the miscarriage or abortion, you should use extra contraception for the first two days of pill taking.
Your pill should be taken at the same time each day. If you forget to take a pill, you should take it as soon as you remember and then take the next one at your normal time.
If you are less than three hours late taking a pill you are still protected and don't need to use extra contraception.
If you are more than three hours late taking a pill, you will not be protected against pregnancy and you should use an extra barrier method of contraception (eg condoms) for the next two days, while you continue to take your pills as normal.
If you have unprotected sex in the two days after missing a pill, the Family Planning Association (FPA) recommends that you should take emergency contraception (the morning after pill).
If you are confused about any of this, you can get individual advice for your circumstances from your doctor, pharmacist, local family planning clinic, or by calling the fpa helpline on 0845 122 8690.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
You should tell your doctor or pharmacist what medicines you are using, particularly those listed below, before you start taking this contraceptive. This includes those bought without a prescription and herbal medicines. Likewise, check with your doctor or pharmacist before starting any new medicines while you are taking this contraceptive, so they can check that the combination is safe.
The following medicines speed up the breakdown of the hormones in this contraceptive by the liver, which makes it less effective at preventing pregnancy:
If you regularly take any of these medicines they are likely to make this contraceptive ineffective at preventing pregnancy. It is important that you talk to your doctor about this. Your doctor will recommend that you use a different form of contraception altogether.
If you are prescribed a short course (up to two months) of any of the above medicines they will also make this contraceptive less effective. Your doctor will probably recommend that you temporarily use a different form of contraception to prevent pregnancy. However, if you want to keep taking this pill you will also need to use an additional method of contraception (eg condoms) for as long as you take the liver-affecting medicine and for at least four weeks after stopping it. It is important to discuss your options with your doctor.
Other antibiotics will not affect this pill. However, if you experience vomiting or diarrhoea as a result of taking an antibiotic you should follow the instructions for vomiting and diarrhoea described in the warning section above.
The emergency contraceptive ulipristal (Ellaone) has the potential to make this pill less effective. If you take Ellaone as an emergency contraceptive either before you start Micronor, or while you are taking Micronor, you should use an additional method of contraception such as condoms for 9 days after you take it.
The weight loss medicine orlistat (bought without a prescription as Alli and prescribed as Xenical) can cause severe diarrhoea. If you take either of these medicines while taking Micronor and get severe diarrhoea, you should follow the instructions in the warning section above.
This pill may antagonise the blood sugar lowering effect of medicines for diabetes. If you have diabetes you should monitor your blood sugar and seek advice from your doctor or pharmacist if your blood sugar control seems to be altered after starting this contraceptive.
This pill may increase the blood levels of the following medicines and this could possibly increase the risk of their side effects:
Noristerat is a contraceptive injection containing norethisterone.
Micronor HRT contains a higher dose of norethisterone and is used for hormone replacement therapy (HRT).
Primolut N and Utovlan tablets contain a higher dose of norethisterone and are used for treating menstrual disorders.