Symptom · Pelvis & genitals

Unusual vaginal bleeding

Also known as: abnormal vaginal bleeding, bleeding between periods, intermenstrual bleeding, bleeding after sex, postmenopausal bleeding, spotting

Bleeding from the vagina at a time when a period is not due: between periods, after sex, after the menopause (once a year has passed since the last period), or during pregnancy. Cervical screening is offered to people without symptoms and is not the test for unusual bleeding: bleeding needs the cervix to be looked at directly. The blood may come from the lining of the uterus, the cervix, the vaginal wall or the vulva, and is occasionally confused with bleeding from the urethra or rectum. Stage of life narrows the causes. In the reproductive years hormonal and infective causes are the commonest, and a pregnancy test is part of every assessment. After the menopause even a single episode of light bleeding is treated as a warning sign: most post-menopausal bleeding turns out to have a benign cause, most often thinning of the lining of the vagina and of the uterus, but it can be the first sign of cancer of the uterine lining, and NICE guidance treats it as a reason for urgent investigation. Trans men and non-binary people with a uterus usually stop having periods on testosterone; bleeding that starts again needs the same assessment.

Seek urgent care if

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Common causes

Hormonal contraceptionBreakthrough bleeding or spotting is common in the first few months of the pill, patch, implant, injection and hormonal coil, and after missed pills; it usually settles, but bleeding that persists is checked for other causes.
Irregular ovulationIn the first years after periods start, in the years before the menopause and in polycystic ovary syndrome, cycles are unpredictable and bleeding can be irregular, prolonged or arrive between expected periods.
Cervical ectropion and polypsSoft glandular cells on the outer surface of the cervix (common in pregnancy and on the pill) and benign polyps of the cervix or uterine lining bleed easily, typically after sex or as spotting between periods.
InfectionChlamydia, gonorrhoea and pelvic inflammatory disease cause bleeding after sex or between periods, often with discharge, pain or fever; swabs for sexually transmitted infections are part of the assessment.
FibroidsBenign growths of the uterine muscle cause heavy, prolonged periods and sometimes bleeding between them.
Early pregnancyLight spotting around the time of implantation is common, but bleeding in a known or possible pregnancy can signal a threatened or actual miscarriage and always needs assessment.

Less common causes

Ectopic pregnancyLight, often dark bleeding with one-sided pelvic pain, shoulder-tip pain or faintness about six to eight weeks after the last period; a pregnancy outside the uterus can rupture and is an emergency.
Cervical cancerBleeding after sex, between periods or after the menopause, with or without an unusual discharge. Cervical screening is a test for people without symptoms, so bleeding needs the cervix to be examined directly.
Cancer of the uterine liningEndometrial cancer most often presents as post-menopausal bleeding and is more likely with obesity, diabetes, polycystic ovary syndrome or oestrogen taken without a progestogen; it is investigated with a transvaginal ultrasound of the lining and an endometrial biopsy.
Vaginal atrophy and injuryLow oestrogen after the menopause, and in trans men on testosterone, thins the vaginal lining so that it bleeds after sex; injury to the vulva or vagina is another cause. Atrophy is settled on as the explanation only once cancer has been excluded.
Bleeding disorders and anticoagulant medicinesInherited clotting disorders and anticoagulant medicines make menstrual and other bleeding heavier and more prolonged.

Often occurs with

Pelvic painHeavy periodsAbdominal painDizziness

Conditions to read about

Cervical cancerEctopic pregnancyFibroidsPolycystic ovary syndromeEndometriosis

How it is investigated

Pregnancy testCervical screening (smear test)Full blood countHormone testsMicrobiology testsBiopsy
Ultrasound
Educational content. This page explains what a symptom can mean so that the anatomy and the medical reasoning make sense. It cannot tell you what is causing yours: only a clinician who can examine you and order tests can do that.