Blood in your urine, called hematuria, is surprisingly common in women and usually points to something treatable like a urinary tract infection or kidney stone. That said, visible blood in your urine always warrants a medical evaluation, even if you feel fine otherwise. The cause can range from completely harmless to something that needs prompt attention, and a few simple tests can usually sort out which category you fall into.
Sometimes the blood is obvious, turning your urine pink, red, or cola-colored. Other times it’s only detectable under a microscope during a routine urinalysis. Both forms matter, though visible blood tends to prompt a faster workup.
Urinary Tract Infections: The Most Common Cause
UTIs are by far the most frequent reason women see blood in their urine. The short length of the female urethra makes it easier for bacteria to reach the bladder, which is why UTIs are so much more common in women than men. Along with pink or red-tinged urine, you’ll typically notice a burning sensation when you pee, a persistent and urgent need to go, passing only small amounts each time, and pelvic pressure or pain centered around the pubic bone.
A simple urine culture confirms the diagnosis, and a short course of antibiotics clears most infections within a few days. If the infection travels to the kidneys, symptoms escalate to include fever, back or side pain, and sometimes nausea. Kidney infections need more aggressive treatment and shouldn’t be ignored.
Kidney and Bladder Stones
Stones form when minerals in your urine crystallize and clump together. About 85% of people with kidney stones have at least some blood in their urine, though in many cases it’s only visible under a microscope. The hallmark symptom is sudden, severe pain in the flank that radiates down toward the groin or, in women, the labia. Intense nausea and vomiting often accompany the pain.
Smaller stones in the lower ureter can mimic a UTI, causing urinary urgency, frequency, and burning. In women specifically, this presentation sometimes gets confused with ovarian cyst rupture, pelvic inflammatory disease, or even menstrual cramps. Stones that make it into the bladder usually pass without much trouble, though large ones can occasionally block the bladder outlet.
Endometriosis Involving the Urinary Tract
This is a cause unique to women. When endometrial tissue grows on or into the bladder wall, it can trigger blood in the urine that follows a cyclical pattern, appearing around the same time as your period each month. Urinary urgency and frequency often come with it. If you notice that the blood in your urine seems to sync with your menstrual cycle, mention that timing to your doctor. It’s a meaningful clue.
Urinary tract endometriosis is typically diagnosed with ultrasound (transvaginal for bladder involvement, transabdominal if ureteral disease is suspected) or MRI. Women with bladder endometriosis almost always have endometriosis at other sites too, so a thorough history and pelvic exam are important parts of the evaluation.
When Blood in Urine Could Signal Cancer
This is the concern most people are really searching about, and the reassuring news is that the odds are relatively low. A large study of primary care records found that visible blood in the urine was associated with bladder cancer in about 2.8% of people aged 60 and older, and about 1.2% of those between 40 and 59. For blood found only on a urine test, the numbers were even lower: 1.6% for those 60 and up, and under 1% for younger adults.
Still, painless blood in the urine, especially in women over 50 or those who smoke, is taken seriously. Bladder cancer is the most common malignancy found during a hematuria workup, followed by kidney cancer. The absence of pain doesn’t mean the absence of a problem. That’s precisely why painless, visible hematuria often triggers imaging and a direct look inside the bladder with a small camera.
Things That Look Like Blood but Aren’t
Before you panic, consider what you’ve eaten or taken recently. Several foods and medications turn urine red or pink and can convincingly mimic blood:
- Foods: beets (so common it has its own name, beeturia), rhubarb, blackberries, and senna
- Medications: ibuprofen, iron supplements, certain antibiotics like nitrofurantoin and rifampin, the bladder pain reliever phenazopyridine, and a synthetic form of vitamin B12 called hydroxocobalamin
- Red food dyes, particularly Red Dye 40
If you ate a beet salad last night and your urine is pink this morning, that’s probably your answer. But if you can’t trace it to food or medication, don’t assume it’s harmless.
Menstrual Blood vs. Urinary Blood
One of the trickiest diagnostic puzzles for women is figuring out whether blood is coming from the urinary tract or the vagina. Menstrual blood can easily mix with urine during collection, creating a false positive for hematuria. If you notice blood in your urine during or near your period, your doctor may ask you to repeat the urine test at a different point in your cycle to get a clean sample. Using a tampon or menstrual cup before providing the sample can also help isolate the source.
Exercise-Induced Hematuria
Sometimes called “runner’s bladder,” this happens when vigorous physical activity causes the walls of a partially empty bladder to repeatedly slam against each other. It’s most common after long-distance running but can occur with any intense exercise. The bleeding is typically painless and resolves on its own within 48 to 72 hours. If it doesn’t clear up within that window, or if it happens repeatedly, something else may be going on.
What Happens During a Workup
A hematuria evaluation usually starts with a urinalysis and urine culture to check for infection. If infection is ruled out, the next steps depend on your age and risk factors. Imaging, most often a CT scan or ultrasound, looks for stones, masses, or structural problems in the kidneys and bladder. For women at higher risk (older age, smoking history, persistent or recurrent blood), a cystoscopy may follow. That’s a thin, flexible camera inserted through the urethra to directly examine the bladder lining.
In many cases, especially in younger women, the workup reveals a straightforward and treatable cause. Even when no cause is found, which happens in a significant number of cases, the workup itself provides peace of mind by ruling out the serious possibilities.
Symptoms That Need Urgent Attention
Most causes of hematuria aren’t emergencies, but a few combinations of symptoms warrant a same-day visit or trip to urgent care. Passing blood clots in your urine can be painful and may indicate heavier bleeding that needs evaluation. Blood in the urine paired with fever and back or side pain suggests a kidney infection. Sudden, severe flank pain radiating to the groin points to a stone that may be blocking urine flow. And blood in the urine with no pain at all, particularly if you’re over 40, deserves prompt investigation simply because painless hematuria is the classic presentation of bladder cancer, even though benign causes are far more likely.