Etynodiol (Femulen)

What is it used for?

  • Contraception.

How does it work?

Femulen tablets are a type of hormonal contraceptive commonly known as the 'mini pill' or progestogen-only pill (POP). They contain the active ingredient etynodiol, which is a synthetic progestogen, similar to the natural progestogens produced by the body. Etynodiol is metabolised to another progestogen called norethisterone once inside the body.

Femulen tablets prevent pregnancy in three ways.

Firstly, they affect the natural mucus at the neck of the womb (cervix). Etynodiol 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.

Etynodiol 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, etynodiol may prevent the release of an egg from the ovaries, however this may not occur in all women who take the mini-pill.

How do I take it?

Femulen 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.)

Femulen 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.

When can I start taking it?

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.

What do I do if I forget to take a pill?

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.


  • The information and advice that we give in this factsheet is likely to conflict with the information you will find in the manufacturer's leaflet provided with your pills. The information and advice we give in this factsheet are the same as the UK Family Planning Association's recommendations, which are based on systematic reviews of the currently available evidence. If you are concerned or have any questions, you can ask your doctor, nurse, pharmacist or local family planning centre for advice.
  • If you vomit within two hours of taking a pill, or have severe diarrhoea, this may affect the absorption of this pill into your bloodstream and could make it less effective at preventing pregnancy. You should use extra contraception, eg condoms, during the stomach upset and for two days after you recover, while continuing to take your pills as normal.
  • This contraceptive pill will not protect you against sexually transmitted infections, so you may still need to use condoms as well.
  • The progesterone only pill can often cause menstrual irregularities, such as irregular bleeding or missed periods. These can be annoying, but tend to settle down after a while. If you have continued problems with irregular bleeding you should talk to your doctor. If you are worried that you could be pregnant because you have not had a period, you should ask your doctor or nurse for advice or do a pregnancy test. However, if you took all your pills correctly and you didn't have an upset stomach or take any other medicines which might affect the POP (see end of factsheet), then it is unlikely you are pregnant.
  • Women who do get pregnant while using a progesterone-only contraceptive may have a greater risk of the pregnancy occuring outside the womb (ectopic pregnancy) than women using other forms of contraception. (However, the risk is still lower than in women who don't use any contraception at all.) You should consult your doctor if you experience any sudden or abnormal abdominal pain while you are taking this pill, particularly if you also have no bleeding, or shorter or lighter than normal bleeding.
  • It is important to be aware that women using hormonal contraceptives appear to have a small increase in the risk of being diagnosed with breast cancer, compared with women who do not use these contraceptives. However, this risk must be weighed against the benefits of using the contraceptive, which can be discussed with your doctor.
  • Stop taking this medicine and consult your doctor immediately if you get any of the following symptoms while taking this medicine: migraine or severe headaches, disturbance in vision, stabbing pains and/or unusual swelling in one leg, pain on breathing or coughing, sudden breathlessness, sudden severe chest pain, sudden weakness or numbness affecting one side or part of the body, significant rise in blood pressure, itching of the whole body, yellowing of the skin or whites of the eyes (jaundice), severe abdominal complaints or if you think you could be pregnant.

Not to be used in

  • Known or suspected pregnancy.
  • Women with abnormal vaginal bleeding, the cause of which has not yet been diagnosed.
  • Breast cancer.
  • Hereditary blood disorders called acute porphyrias.

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.

Use with caution in

  • Women who are going to have major surgery with prolonged immobilisation.
  • Women with an active blood clot in a vein, eg in the legs (deep vein thrombosis) or the lungs (pulmonary embolism), or a history of this.
  • Women with disorders that increase the risk of blood clots in the veins, eg antiphospholipid syndrome, antithrombin deficiency or factor V Leiden.
  • Long-term condition called systemic lupus erythematosus (SLE).
  • History of breast cancer (though this injection may be considered for women who have had no evidence of the disease for five years).
  • Women with gene mutations that are associated with breast cancer, eg BRCA1.
  • Liver cancer.
  • Severe liver cirrhosis.
  • Gallbladder disease.
  • Women with a history of jaundice or itching caused by previous use of an oral contraceptive.
  • Inflammatory bowel disease.
  • History of serious disease of the arteries, eg that has caused a stroke, angina or heart attack.
  • Women with multiple risk factors for heart disease, such as smoking, high cholesterol, high blood pressure, diabetes.
  • Women with raised levels of fats such as cholesterol or triglycerides in their blood.
  • Diabetes.
  • History of migraine.

Pregnancy and breastfeeding

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.

  • This medicine is used to prevent pregnancy and should not be taken during pregnancy. However, if the pill fails or you miss pills and you do get pregnant while taking it, there is no evidence to suggest that the pills you have already taken will harm the baby. If you think you could be pregnant while taking this pill you should stop taking it and consult your doctor immediately.
  • Small amounts of the hormone in this pill may pass into breast milk, however there are no known harmful effects on the nursing infant when it is used by breastfeeding mothers. It does not affect the production of breast milk.

Side effects

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.

  • Changes in menstrual bleeding, eg irregular bleeding or sometimes stopping of bleeding.
  • Nausea and vomiting.
  • Headache/migraine.
  • Changes in sex drive.
  • Changes in appetite and weight.
  • Breast tenderness.
  • Skin problems, eg spots.
  • Depression.
  • Cysts on the ovaries.
  • Increase in size of uterine fibroids.
  • Dizziness.

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.

How can this medicine affect other medicines?

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:

  • aprepitant
  • bosentan
  • barbiturates
  • carbamazepine
  • eslicarbazepine
  • nevirapine
  • oxcarbazepine
  • phenobarbital
  • phenytoin
  • primidone
  • rifampicin
  • rifabutin
  • protease inhibitors such as ritonavir
  • the herbal remedy St John's wort (Hypericum perforatum)
  • topiramate.

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 Femulen, or while you are taking Femulen, 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 Femulen 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:

  • lamotrigine
  • selegiline (should be avoided in combination with the pill)
  • tizanidine.

Other medicines containing the same active ingredient

There are currently no other medicines available in the UK that contain etynodiol as the active ingredient.