Oral contraceptive covers two quite different medicines, and almost every practical question depends on which one you take.
- Combined pills contain an oestrogen and a progestogen. They usually give a regular monthly bleed, often improve acne, and carry a small blood clot risk. Most packs have a break or inactive tablets.
- Progestogen-only pills, also called mini pills, contain one hormone. Bleeding is unpredictable, there is no clot risk of the same kind, and they are taken continuously with no break.
How to tell which you are on: if your pack has a break week or differently coloured inactive tablets and you get a predictable bleed, it is almost certainly combined. If every tablet is identical and you take one every day without a break, it is progestogen-only. A pharmacist can confirm from the box in seconds.
Common hormonal medicine side effects
Both share a group of early effects that usually settle within two to three months: irregular bleeding or spotting, breast tenderness, headaches, nausea, mood changes, bloating and changes in sexual desire.
Where they differ: combined pills tend towards a predictable cycle and often help acne, while progestogen-only pills tend towards unpredictable bleeding and may worsen acne in some people.
See combined pill side effects and progestogen-only pill side effects.
Bleeding, mood, skin, weight and cycle changes
Give either around three months before judging it, unless something is seriously wrong. Effects that persist beyond that are worth changing method over rather than tolerating, and there are enough alternatives that persisting with one that does not suit you is rarely necessary.
See spotting on birth control and birth control and mood.
Serious warning signs that need medical attention
Get emergency help for signs of a clot or stroke, which apply mainly to combined pills:
- Pain, swelling or redness in one calf or thigh
- Sudden breathlessness or chest pain worse on breathing in
- Sudden severe headache, one-sided weakness, difficulty speaking, or loss of vision
- Severe abdominal pain, or yellowing of the eyes or skin
See hormonal medicine and blood clot symptoms.
Who may be at higher risk?
Migraine with aura, smoking over 35, a history of blood clots, high blood pressure and recent childbirth all steer away from combined pills. In most of those situations a progestogen-only method remains an option, so these are usually reasons to change type rather than to have no method at all.
Vomiting, severe diarrhoea, some epilepsy medicines, rifampicin and St John’s Wort reduce effectiveness of both. Missed-pill rules differ between the two types, so read the ones for your pill.
What to discuss with your doctor, pharmacist or clinic
- Which type am I on, and what are my missed-pill rules?
- Given my history, is a combined pill suitable?
- How long should I give this before deciding?
- If it does not suit me, what would we try next?
- Which symptoms need emergency care?
Related contraception, HRT and hormonal medicine guides
- Hormonal contraception side effects
- Birth control side effects
- Women’s health and hormonal medicine side effects
- When to see a doctor about hormonal medicine
- Report a hormonal medicine side effect
See also contraceptive pill side effects.
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.