The progestogen-only pill contains one hormone rather than two. That single difference explains most of what follows: it can be used by people who cannot take oestrogen, it does not carry the same clot risk, and its main drawback is unpredictable bleeding.
There are two types, and knowing which you are on matters, because the timing rules differ substantially. Traditional progestogen-only pills, containing levonorgestrel or norethisterone, need to be taken within about a three-hour window each day. Desogestrel pills allow around twelve hours. Taking a traditional one three hours late is a missed pill; taking a desogestrel one three hours late is not. Ask your pharmacist which you have.
Common hormonal medicine side effects
- Changes to bleeding, the most common effect by far. Bleeding may become irregular, more frequent, lighter, or stop altogether.
- Headaches
- Breast tenderness
- Acne, or a change in skin
- Mood changes
- Ovarian cysts, which usually resolve without treatment
- Changes in sexual desire
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
Bleeding is the main reason people stop. Roughly speaking, some have no bleeding at all, some have regular bleeding, and some have frequent or prolonged spotting. There is no way to predict which you will get, and the pattern that emerges over the first few months tends to be the pattern that continues.
Periods stopping altogether is not harmful and does not mean anything is building up. See irregular bleeding on hormonal medicine.
Mood changes are reported and are a legitimate reason to change method. Acne may improve or worsen. Weight gain is not well established for this method, though it is often attributed to it.
Serious warning signs that need medical attention
Contact a doctor promptly for: a missed period with abdominal pain, which needs assessment to exclude pregnancy including ectopic pregnancy; severe or persistent pelvic pain; very heavy or prolonged bleeding; severe headache unlike your usual; yellowing of the eyes or skin; or a new breast lump.
Bleeding that begins after a settled pattern, or that continues heavily beyond the first months, is worth investigating rather than tolerating.
Who may be at higher risk?
Tell your clinician about unexplained vaginal bleeding not yet investigated, liver conditions, a history of breast cancer, or a previous ectopic pregnancy.
Things that reduce effectiveness: vomiting or severe diarrhoea within hours of a pill; taking a pill outside its window; some epilepsy medicines and rifampicin; and St John’s Wort. See St John’s Wort and birth control.
It does not protect against sexually transmitted infections.
What to discuss with your doctor, pharmacist or clinic
- Which type am I on, and what is my missed-pill window?
- Exactly what should I do if I take one late or miss one?
- How long should I give the bleeding pattern before deciding?
- What can be done if bleeding does not settle?
- Do any of my medicines or supplements affect it?
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 the mini pill and combined 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.