Breakthrough bleeding on the birth control pill

It can occur after starting or changing pills, with missed or late doses, during illness that affects absorption, or when medicines interfere with hormone levels. It does not automatically mean the pill has stopped working, but incorrect use can reduce pregnancy protection.

Hormonal contraception keeps the womb lining thin, and small amounts can shed unpredictably while the body adjusts. Continuous pill schedules can also produce spotting. Bleeding can have another explanation, particularly when it starts after a previously stable pattern.

Chlamydia may present with bleeding between periods or after sex, and endometrial polyps can present with irregular bleeding. Neither condition can be identified from breakthrough bleeding alone. Pregnancy, cervical changes and other gynaecological causes may also need consideration according to symptoms and history.

Continue the pill according to its instructions unless a clinician advises otherwise. Review whether any tablets were late or missed, whether vomiting or severe diarrhoea occurred, and whether a new prescription or herbal product could interact. Use the product guidance for backup and emergency contraception.

Keep a record of bleeding days, dose errors, pain and bleeding after sex. Consider a pregnancy test when pill use has been unreliable or pregnancy symptoms occur. Sexual health testing may be appropriate after a new partner or possible exposure, even without discharge or pain.

Obtain urgent care for very heavy bleeding with faintness, weakness, breathlessness or chest pain. Severe or one-sided pelvic pain, shoulder-tip pain or collapse with possible pregnancy needs emergency assessment for ectopic pregnancy or another acute cause.

Arrange a prompt appointment if bleeding persists, returns after a stable pattern, occurs after sex, is accompanied by pelvic pain or unusual discharge, or follows a possible sexually transmitted infection exposure. Do not rely on changing pill brands to treat unexplained bleeding.

Ask whether your pill schedule, missed doses or other medicines explain the pattern; whether pregnancy or infection testing is suitable; what examination may be needed; and how to switch methods without leaving a gap in contraception.