What should you know about black blood between periods?

Blood darkens as it remains in the uterus or vagina and is exposed to oxygen, so colour alone cannot identify the cause. Note whether the discharge is truly bloody, how much there is, and whether it occurs with pain, odour, fever, bleeding after sex, pregnancy symptoms, or a missed period.

Small amounts of older menstrual blood may leave the body after a period. Bleeding between periods can also occur with hormonal changes, contraception, irritation, infection, pregnancy-related problems, or growths such as endometrial polyps and uterine fibroids. Chlamydia can cause bleeding between periods or after sex, sometimes with discharge or pelvic discomfort.

Cervical dysplasia, cervical cancer, and womb cancer can present with unexpected vaginal bleeding, but the appearance of the blood cannot diagnose any of these conditions. A clinician uses the timing, examination, pregnancy testing, infection testing, cervical screening history, and sometimes imaging or sampling to work out the cause.

Record the dates, colour, amount, clots, pain, discharge, and whether bleeding follows sex. Also note your last normal period, contraception, medicines, recent procedures, and any chance of pregnancy. Arrange a medical appointment if bleeding recurs, persists, begins after menopause, follows sex, or is accompanied by unusual discharge or pelvic pain.

If pregnancy is possible, take a pregnancy test and seek clinical advice about unexpected bleeding. Avoid self-treating presumed infection with leftover antibiotics, because testing helps select the appropriate treatment and identifies whether a partner may also need care. Continue prescribed contraception unless a clinician advises a change.

Seek urgent medical care for heavy bleeding, fainting, severe or worsening pelvic pain, shoulder-tip pain, marked weakness, difficulty breathing, or bleeding during a possible pregnancy. Fever with pelvic pain or foul-smelling discharge also needs prompt assessment. Bleeding after menopause should be evaluated even when it is light or happens only once.

Ask which causes fit the timing and accompanying symptoms, whether pregnancy or infection testing is appropriate, and whether your cervical screening is up to date. You can also ask whether a pelvic examination, ultrasound, or womb-lining sample is needed, what changes should prompt urgent help, and when to return if the bleeding continues.