Progestogen-only Contraceptive Pill POP
The progestogen-only contraceptive pill is commonly used when the combined pill is not suitable. It can also be safely taken if you are breastfeeding.
The progestogen-only pill (POP) is an effective method of contraception if used correctly. It is often used if the combined pill (which contains oestrogen as well as a progestogen) is not suitable. It can also be safely taken if you are breastfeeding.
In North America it is called the progestin-only pill.
You can read more about the combined pill in our separate leaflet called The Combined Oral Contraceptive (COC) Pill.
How does the progestogen-only pill work?
The POP contains a progestogen hormone. This hormone is similar to the progesterone hormone made by the ovaries. A progestogen is also the hormone that is in several other types of contraceptives. You can read more about these other types of progestogen contraceptives in our separate leaflets called Contraceptive Injection, Contraceptive Implant, Intrauterine System (IUS) and Emergency Contraception.
The progestogen hormone in older (traditional) POPs is either levonorgestrel or norethisterone. Brands currently available in the UK are Micronor®, Noriday® and Norgeston®. A newer type of POP contains a progestogen hormone called desogestrel. Brands currently available include Cerazette®, Aizea®, Cerelle® and Feanolla®.
Older POPs work mainly by thickening the sticky mucus made by the neck of the womb (cervix). The mucus forms a plug in the cervix. This stops sperm from getting through to the womb (uterus) to fertilise an egg.
POPs also have some effect on the ovary. Your ovaries do not release an egg (ovulate) as often when you take the POP. The newer type of POP containing desogestrel stops ovulation most of the time. Stopping ovulation is the main way these newer pills work.
How effective is the progestogen-only pill?
Between 3-80 women in 1,000 using the POP will become pregnant each year. (If no contraception is used, more than 800 in 1,000 sexually active women become pregnant within one year.) Correct use gives the lower figure (3 per 1,000) and includes taking the pill exactly according to instructions, at the same time every day. If it is not taken correctly, more women will become pregnant (80 per 1,000).
Why would I choose the progestogen-only pill?
- Taking the POP does not interfere with sex.
- You can take it any time after childbirth, including immediately after delivery.
- You can take it when you are breastfeeding.
- It has a lower dose of hormone than the combined pill.
- The POP does not give you a higher risk of blood clots (unlike the combined pill). It can therefore be used by some women who cannot take the combined pill. For example, if you are aged over 35 and smoke, if you have migraines, or if you have high blood pressure.
Are there any problems with using the progestogen-only pill?
- You have to remember to take the pill at exactly the same time every day. For older POP brands, this means within three hours of the time you took it the day before; for POPs containing desogestrel, within 12 hours.
- It can give you irregular periods. See the section below.
- It can give you some side-effects, although these are usually mild. See the section on side-effects.
- It cannot be taken with some kinds of other medication. See the section about medicines which interfere with the POP.
- It may mean you are more likely to develop cysts in your ovaries. If this happens they are usually very small and do not need any treatment.
- It may (like the combined pill) give you a very small increased risk of breast cancer.
- If you do become pregnant while taking the POP, there is a small risk that it might be an ectopic pregnancy. However, ectopic pregnancy is still far less likely when taking the POP than when not using any contraception.
What happens to your periods when you take the progestogen-only pill?
The effect on periods can vary. Some women taking the POP continue to have regular normal periods. However, some have irregular periods, some have very infrequent periods and some have no periods at all. Some women also have occasional 'spotting' between periods.
Changes in bleeding patterns when taking the POP are common:
- 2 in 10 women have no bleeding.
- 4 in 10 women have regular bleeding.
- 4 in 10 women have irregular bleeding.
You should continue to take the POP every day, including when you have periods. However, if you do develop irregular bleeding while taking the POP, you should inform your doctor. Irregular bleeding can sometimes be due to another reason - for example, an infection, which may need to be treated.
Are there any side-effects with taking the progestogen-only pill?
Side-effects are very uncommon. If one or more do occur, they often settle down over a couple of months or so. Examples of possible side-effects include mood swings, increase in acne, and breast discomfort. There is no evidence that the POP causes women to put on weight.
Dr Krishna Vakharia, 24th March 2023
There has been a recently published study that has reported that there could be an increased risk of breast cancer in all forms of progesterone contraception: pill, implant, injection and coil. They have observed that this risk is between 20-30%, which on paper looks very high.
They found that if people took progesterone contraception for five years, overall they would have an increased risk over 15 years of an extra 8 women per 100,000 women in 16- to-20-year-olds and up to 265 extra cases of breast cancer per 100, 000 women in th 35-39 age range.
Of note, the risk of breast cancer in the 16- to 20-year-old group is extremely small so this added extra over 15 years is still very, very small. As you age, the risks of cancer, including breast, become higher. The risks and benefits have to be weighed up and your doctor will discuss this with you. It must be remembered that excess alcohol can increase your risk of breast cancer by 20% as well, as can having problems with obesity.
Overall, whilst weighing up the risks - pregnancy, and all the potential risks that entails such as blood clots, gestational diabetes as well as the emotional trauma of an unwanted pregnancy or termination - need to be taken into account too.
Who cannot take the progestogen-only pill?
Most women can take the POP and it can safely be taken until you are 55 years of age. See our separate leaflet called Contraception for the Mature Woman for more information.
Your doctor or family planning nurse will discuss any current and past illnesses.You should not take the POP if you have breast cancer, or have had it in the past. You also should not take it if you have very severe liver disease, or liver tumours. If you take certain medications you may not be able to take the POP, especially if you are on medication for epilepsy. See the section on other medicines below.
How do I take the progestogen-only pill?
Start taking the pill on the first day of your next period. It is immediately effective from then on. It will also start to work straightaway if you begin taking it up to the fifth day from the start of your period. (ie if Day 1 is the first day of your period, you can begin taking it on Day 1, 2, 3, 4 or 5 and it will work straightaway.) If you start on any other day, you should use additional contraceptive methods (such as using condoms or not having sex) for the first 48 hours. This is until the POP has become effective.
If you have just had a baby, the POP is immediately effective if you start taking it before Day 21 after the birth. If you begin taking it after Day 21, use additional contraception (for example, condoms or not having sex) for 48 hours.
You should take the POP at the same time of day, every day. Any time of day will do but the most important thing is to get into a routine. Do not stop taking it when you have a period. You should take it every day. When you finish one pack, start another the next day. If you take a pill more than three hours later than usual for the traditional pills, you lose protection (see below). If you are taking a newer pill containing desogestrel, you have a 12-hour window to take your pill. If you are more than 12 hours late, you will need to use extra protection.
If you are switching to the POP from a different type of contraception or after using emergency contraception, discuss starting the new pill with your doctor or nurse. The safest way to start the pill and the need to have additional contraception is different - when changing from - for some methods.
What if I forget to take a pill?
If you forget to take a POP, take it as soon as you remember. This may mean that you take two pills in one day (do not take more than one missed pill).
For older POPs
If you are more than three hours late in taking it (more than 27 hours since your last pill) then your protection immediately fails.
For the desogestrel POP
If you are more than 12 hours late in taking it (more than 36 hours since your last pill) then your protection immediately fails.
For all types of POP
- Continue taking your pill each day, but you will need to avoid sex, or use extra contraception (such as condoms) for 48 hours, until the POP becomes effective again.
- If you have had unprotected sex (without a condom) after the missed pill or in the 48 hours that followed it, you will need emergency contraception.
What if I am vomiting or have diarrhoea?
If you are sick (vomit) within two hours of taking your POP or have severe diarrhoea, the pill will not be absorbed. Carry on taking the POP as usual but use other forms of contraception (such as condoms) for the duration of the illness plus for a further 48 hours after the vomiting or diarrhoea has stopped.
Do other medicines interfere with the progestogen-only pill?
Some medicines may interfere with the POP and make it less effective. Tell the doctor or pharmacist that you take the POP if you are prescribed or buy another medicine. Medicines which interfere with the POP include:
- Some medicines for epilepsy - for example, carbamazepine, oxcarbazepine, eslicarbazepine, phenytoin, phenobarbital, primidone and topiramate. Some of these pills are used for other problems - for example, migraine or pain.
- The antibiotics rifampicin and rifabutin. (Other antibiotics do not affect the POP.)
- Some medicines used to treat HIV and AIDS - for example, nevirapine and ritonavir.
- St John's wort. This is a treatment bought over the counter and sometimes used for depression. Your doctor may not know you are on it, so you should mention it. The POP may not work if you are taking St John's wort.
- Ulipristal acetate. This is a medicine which comes in two forms - as ellaOne® for emergency contraception, and Esmya® for fibroids. If you take the POP after using ellaOne®, you should not take a POP for five days. This is because the POP can stop the ellaOne® from working. You will need to avoid sex or use a barrier contraceptive (eg, condom) for seven days from the day you took ellaOne®. If you take Esmya® you should not use the POP. You should also not take it for 12 days after finishing it.
Further reading and references
Progestogen-only Pills; Faculty of Sexual and Reproductive Healthcare (August 2022, amended November 2022)
CEU Clinical Guidance: Emergency Contraception; Faculty of Sexual and Reproductive Healthcare (March 2017 - updated December 2020)
CEU Clinical Guidance: Contraception After Pregnancy; Faculty of Sexual and Reproductive Healthcare (January 2017, amended October 2020)
Contraception - progestogen-only methods; NICE CKS, March 2021 (UK access only)
UK Medical Eligibility Criteria Summary Table for intrauterine and hormonal contraception; Faculty of Sexual and Reproductive Healthcare, 2016 - amended September 2019
Trussell J; Contraceptive failure in the United States, Contraception, 2011
Combined and progestagen-only hormonal contraceptives and breast cancer risk: A UK nested case–control study and meta-analysis; Public Library of Science (PLOS, March 2023