Blood in semen (hematospermia): causes and when to get tested

Semen is a mixture of sperm from the epididymides and fluids from the accessory glands: the seminal vesicles (about 60–70% of the volume), the prostate and the small urethral glands. Blood may come from any of these sites, and also from the vas deferens, the urethra or the bladder. The thin-walled vessels of the lining of the seminal vesicles and prostate are prone to injury, whether from inflammation, trauma, calcifications or after a procedure.

In practice the causes are divided into several groups. Inflammatory and infectious causes include prostatitis and inflammation of the seminal vesicles, urethritis (including chlamydial) and epididymitis; mechanical causes include stones and calcifications of the seminal vesicles or prostate, cysts, strictures and obstruction of the ejaculatory ducts; iatrogenic causes include prostate biopsy, cystoscopy, catheterisation, radiotherapy or brachytherapy of the pelvis, and vasectomy. Less common are vascular lesions, tumours (of the prostate, seminal vesicles, testicle or bladder) and systemic causes: hypertension, bleeding disorders, liver disease and anticoagulant treatment. In very many cases, despite tests, no clear cause is found.

Both series have limitations that should be kept in mind. The first uses billing data: it allows diagnosed cancers to be counted, but it is not known whether tests were done in everyone, and the accuracy of coding is not certain. The second comes from a single referral centre, so it may have included patients with more risk than the general population. Even so, the picture is consistent: the great majority of cases are benign and cancer is rare but not impossible, particularly after the age of 40, when in the large analysis it was diagnosed in 0.11% of men with hematospermia, compared with 0.01% below that age.

If blood in the semen appeared after a prostate biopsy, this is the commonest and usually the least worrying situation. The needle damages vessels of the prostate and seminal vesicles, and blood in the semen may be visible for several weeks and sometimes longer, and usually needs no treatment. For this reason doctors often warn patients about this course before the procedure. It is still worth seeing a doctor if the hematospermia is accompanied by fever, chills, pain or difficulty urinating (a possible infectious complication), or if the bleeding is very heavy or shows no tendency to subside.

Similar rules apply to other pelvic procedures: cystoscopy, catheterisation, vasectomy, brachytherapy or radiotherapy. In these situations it is known where the blood came from, so observation is usually enough. When hematospermia does not resolve after several weeks or gets worse, the doctor may consider additional tests. A separate case is recurring episodes after a long period of sexual abstinence or after very intense sexual activity: many of these resolve on their own, but there are no good data that would allow the symptom to be attributed solely to such factors, so a recurrence deserves assessment.

The foundation is the history: duration and number of episodes, colour and amount of blood, blood in the urine, pain, fever, urinary symptoms (frequency, urgency, weak stream), risky sexual contacts, recent procedures, pelvic injuries, medicines taken (especially anticoagulant and antiplatelet), coexisting diseases (hypertension, liver disease, bleeding disorders) and travel to regions where schistosomiasis occurs. Next comes the physical examination: of the genitals, groins and scrotum, a digital rectal examination (prostate) and a blood pressure measurement. The basic laboratory test is a urinalysis, which detects hematuria that changes the risk assessment, with a culture if there are symptoms of infection.

PSA is sometimes ordered in men over 40–50, but its interpretation in hematospermia needs caution: inflammation, recent ejaculation, instrumentation and biopsy can raise the result, so the measurement is best discussed with the doctor and, in case of doubt, repeated once transient causes have resolved. We write separately about the causes of a raised PSA other than cancer. In Hakam's analysis only 11.9% of men with benign hematospermia had a PSA measured, and yet few cancers were diagnosed; this is not, however, an argument for giving up PSA in men at risk, only a hint that the decision is individual.

Imaging is not needed in every case. In a young man with one episode, a negative urinalysis and normal blood pressure, most doctors stop at observation. Imaging is considered when the hematospermia recurs or persists, occurs after 40, is accompanied by other symptoms, or when the first tests do not explain the cause. The usual start is ultrasound: transrectal (TRUS) of the prostate and seminal vesicles, possibly with a scrotal ultrasound, which detects cysts, stones, dilatation and some focal lesions. MRI (especially of the prostate and pelvis) has higher soft-tissue resolution and is chosen for recurrences, an equivocal ultrasound or suspected tumour; it is, however, more costly and less readily available. Cystoscopy is performed mainly with accompanying hematuria or suspected lesions of the bladder or urethra.

Blood in semen deserves attention, not panic. The outcome of the assessment is usually reassuring, but a few simple tests organise the picture and allow the rare cases whose cause needs treatment to be found. A sensible attitude is to see a doctor promptly but without alarm at the first episode, to have a full work-up for recurrences or after age 40, and to react at once to warning signs. The evidence we rely on comes from observational studies and reviews of moderate quality.