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:

  1. Brachytherapy
  2. Chlamydia
  3. Epididymitis
  4. Genital herpes
  5. Gonorrhea
  6. Interrupted sex
  7. Prolonged sexual abstinence
  8. Prostate biopsy
  9. Prostatitis
  10. Testicular trauma
  11. Vasectomy
  12. Vigorous sex

Less common causes

  1. Amyloidosis
  2. Benign growths (cysts, polyps) in the bladder, urethra or prostate
  3. Anterior prolapse (cystocele)
  4. Fragile blood vessels
  5. Second trimester pregnancy
  6. Prostate cancer
  7. Schistosomiasis
  8. Testicular cancer
  9. Thrombocytopenia
  10. Tuberculosis
  11. Von Willebrand disease
  12. Warfarin side effects

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

Aug. 16, 2012