Everything you need to know – Progestogen-only pill (POP)


by Maddie Braidwood · Aug 28, 2020

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Reviewed by Dr. Melanie Davis-Hall on July 9, 2021

Progestogen-only pill graphic
What is the progesterone only pill? The progesterone only / mini pill (POP) is a small tablet you swallow daily that (unlike the combined pill) only contains one hormone – progesterone, and is often used by women that can’t tolerate oestrogen. This means fewer than 1 in 100 women who use the progestogen only pill as contraception will get pregnant in 1 year.

How effective is the progestogen-only pill?

The progestogen-only pill, better known as the progesterone only pill, mini pill or POP, is a form of contraceptive pill which contains synthetic progestogen, similar to progesterone naturally produced by the female body. It is often used by women who are unable to use combined contraception which contains oestrogen, such as if you are breastfeeding or have a history of migraines.

Designed to be taken at the same time every day, the mini pill is one of the more popular contraceptives with common brands including Cerelle, Cerazette, Norgeston and Noriday.

The progestogen-only pill is 99% effective if taken as directed at the same time each day. But, if this mini pill is taken in a ‘typical’ way, i.e not strictly at the same time each day, its effectiveness drops to 92-93%.

How does the progestogen-only pill work?

It prevents pregnancy by making the fluid in your cervix thicker (which makes it more difficult for sperm to enter the womb) and preventing the lining of your womb thickening enough for a fertilised egg to implant into it. The progestogen-only pills with desogestrel in them (so all of them except Micronor, Noriday and Norgeston) can also stop ovulation.

How do I get started on the progestogen-only pill?

If you get your pill via an NHS prescription through your GP, nurse or sexual health clinic, your doctor or nurse may check your medical history, any medicines you take and make sure that you’re not pregnant. You can also buy the progestogen-only pill through pharmacies – The Lowdown has its very own ordering service! Some brands of progestogen-only pill over the counter from July 2021 without a prescription. 

Most women can start the pill at any time in their period cycle if they are sure they are not pregnant. If you start the pill within the first 5 days of you menstrual cycle (within the first 5 days of starting your period), you will be protected from pregnancy straight away. At any other time in your cycle you will need to use condoms for two days until you’re covered. Speak to a health professional for advice if you are switching from another hormonal method of contraception. There are special instructions for starting the pill if you have just had a baby, abortion or miscarriage.

There are normally 28 pills in a pack, and unlike the combined pill you do not have a break between packs. It’s really important you reliably take the progestogen-only pill at the same time every day. There are two different types of progestogen-only pill:

If it helps, keep your pill packet somewhere you use or look at every day (like your makeup bag) to remind you to take it, or set an alarm on your phone. You will normally be given a prescription for the pill for three months or up to one year at a time. If you want to read experiences from our Lowdown users, check out our progesterone only pill reviews.

How do I come off the progestogen-only pill?

Stopping the pill is easy – you just stop taking it. As soon as you stop taking it, you’re no longer protected from pregnancy. If you want to switch to another method it is best to discuss this with your doctor or nurse before stopping your pill. You can also read our blog on switching contraception for more info. Check out our survey results to see how long it took most women’s cycles to return to their definition of ‘normal’, and read up about after effects they’ve experienced.

Pros of the progestogen-only pill

  • Doesn’t interrupt sex
  • Can use it when breastfeeding
  • Can use at any age – even if you smoke and are over 35
  • It’s useful if you can’t take the hormone oestrogen, which is in the combined pill, contraceptive patch and vaginal ring
  • It can stop your periods or make them lighter, less frequent and less painful
  • It may help with the symptoms of premenstrual syndrome

Cons of the progestogen only pill

  • Vomiting and diarrhea will impact on how the pill is absorbed into your body. If you’re sick within two hours of taking the pill you’ll need to take another pill straight away and the next pill at the usual time. If you’re sick or have severe diarrhea for longer than this, check your pill packet for what to do next – and use condoms or abstain if you have any doubts.
  • Some medicines and antibiotics (like rifampicin and rifabutin, St John’s wort and anti-epilepsy drugs) change the way your body digests the pill, speak to your pharmacist for advice if you start a new medicine whilst taking the progestogen-only pill
  • The POP doesn’t protect you from sexually transmitted infections so remember you need to use condoms for this.

Possible side effects

These include the areas that are reported most frequently by reviewers at The Lowdown: 

  1. Mood changes (60%)
  2. Spots / acne (59%)
  3. Breast pain / tenderness (55%)
  4. Headaches (54%)
  5. Vaginal discharge (53%)
  6. Womb cramps (48%)
  7. Enlarged breasts (44%)
  8. Back pain (41%)
  9. Vaginal bleeding (40%)
  10. Vaginal dryness (38%)

Some users also report changes to sex drive or libido. Most of these are temporary are may settle within the first few months. You should contact your GP or nurse if they persist or are problematic.

The development of small fluid-filled sacs (cysts) on your ovaries are also a possible side effect– they are usually harmless and disappear without treatment.

If you do become pregnant while you’re using the POP, there’s a risk of you having an ectopic pregnancy. 

Will the progestogen-only/mini pill affect my periods?

The progestogen-only pill can affect your periods. They may become lighter, less frequent or stop altogether, which may be beneficial. They may also become irregular or prolonged or you may experience spotting between periods.

How quickly does the progestogen-only/mini pill protect me from pregnancy?

The progestogen-only pill can be started at any time during your cycle, but your protection from pregnancy varies depending on when you start it.

If you start at the beginning of your menstrual cycle (days 1 to 5 of your period) then it is effective immediately and you’ll be protected against pregnancy.

If you start on any other day of your menstrual cycle you won’t be protected immediately from pregnancy until you’ve taken the pill for two days, so you will need to use additional contraception such as condoms. 

Who should use it?

Women: who:

  • can remember to take a pill regularly
  • can’t take oestrogen containing contraceptives

Who shouldn’t use it?

Women who:

  • think they might be pregnant
  • don’t want their periods to change
  • take other medicines that may affect the pill
  • have unexplained bleeding in between periods and sex
  • have had heart disease or a stroke, liver disease or breast cancer

What if I miss taking a pill?

Missing or forgetting to take a pill has happened to the best of us. Check out the NHS guide which will help you with what to do, depending on how many you’ve missed and where you are in your menstrual cycle. If you have any doubt, then make sure you use alternative contraception such as a condom or don’t have sex until you’re protected.

Where can you get the progestogen-only pill?

In the UK, you should be able to get a free NHS prescription for the progestogen-only pill in most contraception clinics, sexual health clinics, GPs surgeries, and some young people’s services.

The progestogen-only pills Lovima and Hana will be available over the counter from the pharmacy (ie without a prescription) from July 2021.

The Lowdown will start providing Lovima and Hana through our online ordering service in due course, and in the meantime you can buy other brands of the same pill through us!

  1. Family Planning Association

  2. FSRH

  3. NHS UK

  4. MHRA

Maddie is an English Language and Linguistics graduate who is passionate about writing. She writes fun and informative content on the weird and wonderful sides of contraception!