The mini pill is the everyday name for the progestogen-only pill: a contraceptive pill containing one hormone rather than two. It is often chosen by people who cannot take oestrogen, including while breastfeeding, after 35 if they smoke, or with migraine with aura.

The single most useful thing to know about the mini pill is your timing window, because it is not the same for all of them.

People frequently do not know which they are on, and the difference decides whether a late pill is a missed pill. Ask your pharmacist, and read your leaflet’s missed-pill instructions before you need them rather than at midnight.

Common hormonal medicine side effects

Because there is no oestrogen, these methods can often be used by people who cannot take combined pills, including those with migraine with aura and many who smoke over the age of 35. They also do not carry the same blood clot risk. Confirm your own situation with a clinician rather than assuming.

Bleeding, mood, skin, weight and cycle changes

The mini pill does not produce the regular monthly bleed that combined pills do. Expect unpredictability, particularly in the first months: some people bleed more often, some less, and some not at all. Absent periods on the mini pill are normal rather than a sign of a problem.

Because periods can stop, a missed period is not a reliable pregnancy signal on this method. If you are worried, take a test rather than waiting.

See spotting on birth control and birth control and mood.

Serious warning signs that need medical attention

Contact a doctor promptly for a missed period with abdominal pain, severe pelvic pain, very heavy bleeding, a severe headache unlike your usual, yellowing of the eyes or skin, or a new breast lump.

Who may be at higher risk?

Tell your clinician about unexplained bleeding not yet investigated, liver conditions, a history of breast cancer, or a previous ectopic pregnancy.

Vomiting or severe diarrhoea within a few hours of a pill can stop it being absorbed, and should be treated as a missed pill. Some epilepsy medicines, rifampicin and St John’s Wort reduce effectiveness.

What to discuss with your doctor, pharmacist or clinic

Related contraception, HRT and hormonal medicine guides

See also progestogen-only pill side effects and Microval.

Medical Disclaimer: This content is for informational and educational purposes only and does not constitute medical diagnosis, prescription, or professional advice. Always read the patient information leaflet and consult a qualified doctor or pharmacist regarding any medicine or health concern.