The progestogen-only pill

The mini pill contains progestogen without oestrogen. It can be an option if you cannot use contraception containing oestrogen, though a clinician still needs to check whether it suits you. US information calls it a progestin-only pill.

Start with the name on your packet

The NHS groups progestogen-only pills into traditional, desogestrel and drospirenone types. CDC’s US guidance lists norethindrone, norgestrel and drospirenone. The medicine name matters more than the informal label “mini pill” when checking what to do.

These pills make mucus in the cervix thicker, which makes it harder for sperm to reach an egg. They can also stop ovulation and thin the womb lining. How consistently they stop ovulation varies between types of progestogen-only pill.

For effectiveness, the NHS reports over 99% when taken correctly all the time and 91% when not taken correctly all the time. CDC instead says approximately seven out of 100 users become pregnant in the first year with typical use. These estimates differ. They describe what happens across groups of users and cannot tell you exactly what your own protection will be.

Why late-pill windows differ

The traditional pill has a shorter late-pill window than desogestrel, and drospirenone has a longer window again. Check the leaflet for the exact product as the rules may differ from those for a previous prescription. The instructions also depend on how much time has passed.

If a pill is late or missed, speak to a pharmacist promptly and have the packet with you. You may need emergency contraception, and the pill can affect which emergency contraception is suitable. Ask what to do about the next pill and any additional protection; do not try to work that out from a period estimate.

Vomiting or severe diarrhoea can affect absorption. Ask a pharmacist what the leaflet says for your pill and the illness you’ve had. Some medicines and herbal remedies can also affect how well the pill works, so include those when asking for advice.

Bleeding changes and other effects

Bleeding can become lighter, more frequent or stop altogether. Spotting between periods can happen too. At an appointment, describe how often you bleed and how it affects your day. Be clear about what you’d like help with.

Some people report acne, mood changes, weight gain or changes in sex drive. The NHS says there is not enough evidence to say that the pill causes these effects. You can still ask for help if they’re troubling you.

The NHS also describes ovarian cysts, which are fluid-filled sacs on the ovaries. These often disappear without treatment and usually cause no symptoms, though pelvic pain can occur. Sudden or severe pain needs the urgent assessment described below. The NHS also notes a possible link with breast cancer, but says the evidence is limited and any increased risk is very small. A pharmacist or doctor can discuss concerns.

Breastfeeding and checking suitability

The progestogen-only pill can be used after birth and while breastfeeding. Ask your maternity clinician, pharmacist or contraceptive service to confirm when to begin and whether extra protection is needed for your circumstances. The instructions vary with pill type and timing.

Tell the prescriber about past breast cancer, liver or kidney conditions, stroke or cardiovascular disease. The NHS lists these as reasons the pill may be unsuitable. Some medicines and potassium supplements can matter particularly for drospirenone. A pharmacist or doctor can check the whole list with you.

In the US, one type is available without a prescription. Even without a prescription, read the product information and discuss health conditions and other medicines with a pharmacist or doctor. The pill does not protect against STIs; condoms can add protection.

When to ask for help

Call 999 now (UK), or your local emergency number (US and elsewhere), for sudden intense tummy pain with marked dizziness, fainting or collapse.

Contact an urgent GP service or NHS 111 now (UK), or urgent medical care (US and elsewhere), for sudden severe pelvic pain or tummy pain with nausea or vomiting. Get urgent advice now from these services for lower tummy pain mainly on one side if pregnancy is possible, even without a positive test. Do not assume the pill or a cyst explains the pain.

Contact a pharmacist or sexual health clinic today (UK), or a pharmacist, doctor or contraceptive service (US and elsewhere), if a pill is late or missed and you may need emergency contraception.

Book an appointment with your GP or pharmacist (UK), or your doctor or pharmacist (US and elsewhere), if bleeding changes or other side effects are a problem for you.