Breakthrough bleeding and your period

Its timing, flow, and relationship to contraception matter more than colour alone. A single light episode may settle, but repeated bleeding, bleeding after sex, or a notable change in your usual cycle warrants a clinical review.

A menstrual period follows the natural cycle when pregnancy has not occurred. With combined hormonal contraception, scheduled bleeding during a pill-free or inactive-tablet interval is a withdrawal bleed rather than a natural period. Breakthrough bleeding happens at another time. It may appear as spotting or a flow and can occur after starting or changing contraception, inconsistent dosing, vomiting, diarrhoea, or interactions with some medicines.

Other causes may need consideration when the pattern persists. Chlamydia can present with bleeding between periods or after sex. Endometrial polyps can present with irregular or intermenstrual bleeding. Neither can be identified from the appearance of blood alone.

Mark expected periods or withdrawal bleeds and unexpected episodes on a calendar. Include flow, clots, pain, bleeding after sex, missed contraceptive doses, new medicines, and unusual discharge. Follow your contraceptive instructions and check the product guidance after missed doses or stomach illness. Take a pregnancy test if pregnancy is possible; unexpected bleeding does not reliably confirm or exclude pregnancy.

Seek urgent care for very heavy bleeding, fainting, marked dizziness, severe abdominal or pelvic pain, shoulder-tip pain, fever, or bleeding with a known or possible pregnancy. Book a non-urgent assessment if the bleeding recurs, continues despite correct contraceptive use, happens after sex, or comes with pelvic discomfort or altered discharge. A clinician can review pregnancy risk, infection risk, cervical screening history, medicines, and whether examination or imaging is appropriate.

Ask whether the episode fits your contraceptive method, whether any medicines could interfere with it, and whether you need pregnancy or infection testing. Clarify which bleeding pattern should bring you back and whether changing contraception now could make the pattern harder to interpret.