Here are seven causes of blood in urine. 

By Samantha Lauriello
September 09, 2019

Most people pee between six and eight times a day, which means if something unusual is happening with your urine, you're probably going to notice straight away. Peeing blood, for example, can be alarming. But there are many things that can cause it, some more serious than others. 

Gross hematuria, the medical term for when you can see blood in your urine, might make your pee look pink, red, or brown, according to the NIH's National Institute of Diabetes and Digestive Kidney Diseases, or NIDDK. (Microscopic hematuria, on the other hand, means the blood in your pee is only visible under a microscope.) It's important to see a doctor to determine the reason for the bleeding, no matter what other symptoms you're experiencing. 

Here are seven possible causes of blood in urine. 

RELATED: 9 Home Remedies for Preventing and Treating UTIs

Urinary tract infection 

"In women, the most common cause of gross hematuria typically is urinary tract infection," Norm Smith, MD, a urologist with NorthShore University HealthSystem near Chicago, tells Health. UTIs occur when bacteria enter your body through the urethra and multiply in your bladder. Dr. Smith explains the bacteria can cause irritation of the bladder, or cystitis, which can then lead to bleeding. Other symptoms of a UTI include a persistent urge to urinate, pain and burning with urination, and extremely strong-smelling urine. 

Even if you're pretty sure you have a UTI, it's crucial you get checked out by a doctor. "We see all the time a delay in diagnosis of bladder cancer in women who've been treated multiple times for what are thought to be urinary tract infections," Dr. Smith says. 

Strenuous exercise

In rare cases, going really hard at the gym can result in blood in your urine, according to the NIDDK. Doctors aren't totally sure why this happens, but they believe it could be linked to dehydration, trauma to the bladder, or the breakdown of red blood cells that occurs with aerobic exercise. Runners most commonly develop exercise-induced hematuria, but anyone can experience it after a really tough workout. Still, you shouldn't assume exercise is the cause and decide it's not serious. Always see a doctor to be sure. 

RELATED: 9 Causes of Smelly Urine—and What to Do About It

Kidney infection

Kidney infection (or pyelonephritis) is a type of UTI that generally begins in your urethra or bladder and travels to one or both of your kidneys. Dr. Smith says the bacteria can irritate the lining of the kidneys, causing bleeding. He adds that a person with a kidney infection will likely have symptoms similar to those of a UTI, such as persistent urge to urinate, pain and burning with urination, and strong-smelling urine, as well as other symptoms like fever, chills, abdominal pain, nausea, and vomiting. 

Bladder or kidney stone

The minerals in your urine can sometimes form crystals on the walls of your kidneys or bladder. Over time, those crystals can become small, hard stones. Some stones are symptomless, but if one becomes large enough, it can create a blockage in your urinary tract and cause extreme pain. They can also irritate the lining of the urinary tract and in turn cause bleeding, Dr. Smith says. 

To get rid of the stone, your doctor might remove it or break it up into small pieces, according to the NIDDK. Seek medical attention ASAP if you experience pain so severe that you can't sit still or find a comfortable position, as well as nausea and vomiting, or fever and chills. 

Inherited disorders

Some genetic disorders can cause both visible and microscopic blood in your pee. One of those disorders is sickle cell disease, an inherited disorder that causes the body to create abnormally shaped red blood cells, states the NIDDK. Other symptoms of sickle cell disease include episodes of pain, frequent infections, vision issues, and swelling of the hands and feet. 

Alport syndrome, which affects the filtering membranes in the small blood vessels of the kidneys, is another inherited condition that can cause blood in urine. People with Alport syndrome experience progressive loss of kidney function, according to the NIH. Almost all affected individuals have blood in their urine, a sign of kidney malfunction. It can also cause symptoms like swelling, joint pain, hearing loss, and vision problems.

RELATED: What Your Urine Color Says About Your Health

Certain medications

Some drugs can make a person more likely to have blood in their urine, including including blood thinners, pain relievers, and antibiotics, according to the NIDDK. Dr. Smith also says that some patients, especially those who have a condition that causes their bladder to bleed (like a UTI), might notice blood in their urine after taking a blood thinner such as aspirin. He adds that even patients on blood thinners need to be evaluated by a professional to make sure the blood isn't caused by some other factor. 

Some cancers

Don't panic: If you see blood in your urine, it's more likely due to a UTI than cancer. But it's important to be aware of the possibility. Advanced kidney, bladder, or prostate cancer can cause blood in urine. The bleeding typically comes from the tumor itself, Dr. Smith says, though it can also be the result of irritation or inflammation. These cancers can also have symptoms like painful urination, fatigue, and pain in your back, side, or pelvis.

Again, it's probably not cancer, but the slight chance that it could be is exactly why it's so important to have bloody urine checked out by a doctor. 

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