Blood in your pee during pregnancy is typically caused by one of three types of UTIs. However, it may also be caused by underlying health conditions, such as kidney stones.

If you’re pregnant and see blood in your urine, or your doctor detects blood during a routine urine test, it could be a sign of a urinary tract infection (UTI).

A UTI is an infection in the urinary tract typically caused by bacteria. UTIs are more common during pregnancy because the growing fetus can put pressure on the bladder and urinary tract. This can trap bacteria or cause urine to leak.

Read on to learn more about the symptoms and treatment of UTIs, and other causes of blood in the urine.

There are three major types of UTI during pregnancy, each with distinct causes:

Asymptomatic bacteriuria

Asymptomatic bacteriuria is often caused by bacteria present in a woman’s body before she became pregnant. This type of UTI doesn’t cause any noticeable symptoms.

If left untreated, asymptomatic bacteriuria may lead to kidney infection or acute bladder infection.

This infection occurs in about 1.9 to 9.5 percent of pregnant women.

Acute urethritis or cystitis

Urethritis is an inflammation of the urethra. Cystitis is an inflammation of the bladder.

Both of these conditions are caused by bacterial infection. They’re often caused by a type of Escherichia coli (E. coli).

Pyelonephritis

Pyelonephritis is a kidney infection. It can be the result of bacteria entering your kidneys from your bloodstream or from elsewhere in your urinary tract, such as your ureters.

Along with blood in your urine, symptoms may include fever, pain when urinating, and pain in your back, side, groin, or abdomen.

Doctors commonly use antibiotics to treat UTIs during pregnancy. Your doctor will prescribe an antibiotic that is safe for use during pregnancy but still effective in killing bacteria in your body. These antibiotics include:

The Centers for Disease Control and Prevention (CDC) recommends avoiding nitrofurantoin or trimethoprim-sulfamethoxazole, as they have been linked to birth defects.

Blood leaking into your urine could be caused by a number of conditions, whether you are pregnant or not. This may include:

The cause of hematuria cannot always be identified.

Although hematuria is often harmless, it can indicate a serious disorder. If you’re pregnant and you see blood in your urine, make an appointment with your doctor.

Screening for UTI should be part of routine prenatal care. Talk with your doctor or gynecologist to make sure that they’ve done a urinalysis or a urine culture test.