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.

Most often, no cause can be found for blood in semen. In some cases, particularly among men under age 40, infection is a possible cause. Infection is usually accompanied by other signs and symptoms, such as painful urination.

Ruptured blood vessel

A blood vessel in the prostate or seminal vesicles can rupture during sex or ejaculation. This is similar to when the nose bleeds following a sneeze. This may be more likely if the person is taking blood-thinning medications.

There may be a sudden gush of blood or bleeding that lasts for several minutes and then stops.

Some symptoms of a ruptured blood vessel include :

• Blood in the ejaculate
• Red bleeding
• Bleeding that appears suddenly then goes away

Having sex after long periods without it

Long periods of abstinence from sexual intercourse may cause blood to appear in the semen.

When this happens, a person may also notice :

• Bleeding during or after sex
• Blood in the ejaculate
• A single episode of bleeding
• Light bleeding for a day or two

Obstruction

Any of the tiny tubes or ducts in the reproductive tract can be blocked. This can cause blood vessels to break and release small amounts of blood. The condition called BPH, which causes the prostate to become enlarged and pinch the urethra, is also linked to blood in semen.

Blood vessel problems

All of the delicate structures involved in ejaculation, from the prostate to the tiny tubes that carry sperm, contain blood vessels. These can be damaged resulting in blood in the semen.

Injury

Sustaining an injury to the urinary tract or genitals may cause blood to appear in the semen.

Sometimes, a minor injury such as from vigorous sex ruptures a blood vessel in the prostate or seminal vesicles. When this happens, a person may notice a sudden gush of blood that eventually goes away on its own.

Prostate issues

Problems with the prostate may give rise to bloody semen. One of the most common issues is prostatitis. Prostatitis can be a chronic issue due to inflammation or a sudden problem due to an infection. In either case, the person may notice symptoms other than hematospermia, including:

• Blood in the urine
• Painful urination
• Painful sex
• A feeling of fullness or swelling in the rectum or genital area

Anyone can develop blood in the semen, and doctors are often unable to identify a cause.

However, there are certain risk factors that increase the likelihood of experiencing hematospermia. These include :

• Having vigorous sex, especially after a long period of abstinence
• Being over the age of 40
• Having a history of prostate issues, including prostatitis
• Having a family history of prostate disease
• Having a urinary or genital infection

Noticing blood in the semen can be alarming, but for most males who experience this, there is nothing to worry about.

Even when there is a more serious problem, seeking and receiving prompt treatment can prevent it from worsening. For this reason, anyone concerned about blood in the semen should speak to their doctor.