Causes of irregular bleeding between periods

The timing and appearance of blood do not diagnose the cause. Age, pregnancy possibility, contraception, medicines, pain, discharge, bleeding after sex and examination findings help guide which tests are appropriate.

Temporary hormone shifts can make the womb lining shed unpredictably. Starting, missing or changing hormonal contraception can also alter bleeding. Fibroids and endometrial polyps can disturb the uterine lining, while cervicitis, including that caused by chlamydia, may lead to bleeding between periods or after sex.

Cervical dysplasia may have no symptoms, but abnormal cervical tissue can sometimes be found during investigation of bleeding. Cervical cancer or womb cancer can present with irregular bleeding, particularly when bleeding is persistent or occurs after menopause. Their presence cannot be inferred from bleeding alone.

Take a pregnancy test if pregnancy is possible and contact a healthcare professional if the bleeding recurs, persists or concerns you. Keep a calendar of bleeding days, flow, clots, pelvic pain, discharge and whether bleeding follows sex. List contraception, supplements and prescribed medicines, including medicines that affect clotting.

Depending on your circumstances, assessment may involve a pregnancy test, pelvic examination, infection testing, cervical screening when due, blood tests or pelvic imaging. Do not stop prescribed medicine without advice from its prescriber.

Get urgent medical help if unexpected bleeding comes with severe or one-sided abdominal pain, shoulder-tip pain, fainting or marked dizziness when pregnancy is possible. This combination can signal an ectopic pregnancy or significant internal bleeding.

Emergency assessment is also appropriate for blood rapidly soaking through pads, large clots with weakness, breathing difficulty, chest discomfort, confusion, or pale clammy skin. Fever, worsening pelvic pain or foul-smelling discharge needs prompt same-day advice because infection may require treatment.

Ask whether pregnancy and infection have been excluded, whether the cervix needs examination, whether your contraception could explain the pattern, what imaging might show, and when persistent bleeding would justify sampling the womb lining. Confirm how and when you will receive results.