What is hematospermia? The presence of blood in the semen is called hematospermia (or hemospermia). This problem can accompany pain and other complaints or occur independently. Injuries, infections, and diseases of the prostate are common causes of hematospermia. Although the appearance of blood in the semen can be alarming, it is usually not life-threatening and does not necessarily mean that something is wrong. In fact, in many cases there is no clear cause for hematospermia at all. What are the causes of hematospermia? When there is blood in the semen, it usually comes from either the prostate or the seminal vesicles, which produce most of the semen. However, in at least 70% of cases, the exact cause of hematospermia cannot be determined. If the bleeding only happens once, there is very little chance of a serious underlying problem. The most common causes of this type of bleeding include: A burst blood vessel A blood vessel in the prostate or seminal vesicles can burst during sex or ejaculation and cause bleeding similar to a nosebleed after sneezing. This scenario may be more likely if the person is taking blood-thinning medication. There may be a sudden rush of blood or bleeding that lasts for a few minutes and then stops. Some symptoms of a ruptured blood vessel include: Blood in the ejaculate Bleeding that comes on suddenly and then goes away A ruptured blood vessel is usually not a serious health problem. Sometimes, however, an obstruction (clogging), such as from a cyst, can put pressure on the blood vessels, causing them to burst. Sex after long periods of abstinence Long periods of abstinence from intercourse can cause blood to appear in the semen. When this happens, a man may also notice: Bleeding during or after sex; Blood in the ejaculate; A single episode of bleeding; Light bleeding for a day or two Infection In men under 40, infection is the most common cause of blood in semen. In many cases, the infection occurs in the urinary tract, but it can also affect other areas, such as the prostate. This can develop due to common urinary tract infections and sexually transmitted infections. Other symptoms may be noticed with infection, including: Pain or pressure when urinating; Painful sex or painful ejaculation; Swelling in the genital area; Fever or general malaise and nausea; Frequent urination or difficulty emptying the bladder Injury Injury to the urinary tract or genitals can 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 sudden oozing of blood may be noticed, which eventually goes away on its own. More serious injuries can cause swelling, chronic bleeding, and serious damage to the genitals.When this happens, after a blow to the genitals, genital surgery, or a fall, a bloody seminal fluid may be observed that either persists for a long time or appears and disappears. Prostate problems Prostate problems can lead to blood in the semen. One of the most common problems is prostatitis. A 2015 study of 37 men with hematospermia found that two-thirds of them had some form of prostatitis. Prostatitis can be a chronic problem due to inflammation or a sudden problem due to infection. In both cases, the person may notice other symptoms other than hematospermia, including: Blood in the urine; Painful urination; Painful sex; Sensation of swelling in the rectum or genital area References: 1. Lee, G. (2015). Chronic prostatitis: A possible cause of hematospermia 2. Mathers, MJ, et al. (2017). Hematospermia�A symptom with many possible causes 3. Medical News Today. Why is there blood in my semen?