How do I manage a patient who experiences irregular bleeding after sta

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Management of irregular bleeding after starting progestogen-only pill (POP):

If no other symptoms such as pelvic pain, dyspareunia, or post-coital bleeding are present, and speculum and pelvic examination are normal, the irregular bleeding can be assumed to be caused by the POP. Reassure the patient that unscheduled bleeding is common in POP users and may settle with time, although the pattern and duration are unpredictable.
Explain that over 12 months of use, bleeding patterns vary: about 50% of women become amenorrhoeic or have infrequent bleeding, 40% have regular bleeding episodes, and 10% have frequent or prolonged bleeding episodes.
If the bleeding is unacceptable to the woman, consider changing to a different POP or a different contraceptive method, although there is no evidence that changing the progestogen type or dose improves bleeding.
Exclude other causes of irregular bleeding such as pregnancy (perform a pregnancy test), sexually transmitted infections, cervical or endometrial pathology, especially if bleeding persists beyond 3 months or if there are risk factors or new symptoms.
Advise on missed pill rules and ensure correct use of the POP, as missed pills can contribute to bleeding irregularities.
If other symptoms or abnormal examination findings are present, further investigation and referral may be required.

How do I manage a patient who experiences irregular bleeding after starting the progestogen-only pill?