Semen consists of sperm and fluids released by the prostate and other glands. The fluids (also called ejaculate) join the sperm as they pass through a series of tubes to the urethra for ejaculation. A number of things can break blood vessels along this route or along the urinary route to the urethra. Broken vessels then leak blood into the semen, urine or both.
Often, no cause can be found for blood in semen. For men under age 40, infection is the most common cause. Infection is usually accompanied by other signs and symptoms, such as fever, genital or urinary pain, difficulty urinating, or blood in your urine.
For men age 40 and older, blood in semen is a slight predictor of a cancer (malignancy), most often prostate cancer. So a more careful evaluation is merited when this sign appears in this age group. But the risk is low. In follow-up studies of more than 800 men who had blood in their semen, cancer was found in less than 4 percent (on average).
More common causes of blood in semen:
- Genital herpes
- Interrupted sex
- Prolonged sexual abstinence
- Prostate biopsy
- Prostate gland enlargement
- Testicular trauma
- Vigorous sex
Less common causes
- Benign growths (cysts, polyps) in the bladder, urethra or prostate
- Bladder cancer
- Fragile blood vessels
- Prostate cancer
- Testicular cancer
- Von Willebrand disease
- Warfarin side effects
Aug. 16, 2012
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.
- Aslam MI, et al. A management algorithm for hematospermia. Nature Reviews Urology. 2009;6:398.
- AskMayoExpert. Hematospermia. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2012.
- Weiss BD, et al. Hematospermia. http://www.uptodate.com/index. Accessed July 16, 2012.