Based on PubMed | Could blood in my urine be a sign of endometrial cancer, and when should I see a doctor?

Blood in the urine (hematuria) is most often caused by urinary tract conditions such as infection, kidney or bladder stones, or (less commonly) bladder or kidney cancer rather than endometrial (uterine) cancer. ^{[1] [2]} The hallmark and by far the most common early symptom of endometrial cancer is abnormal vaginal bleeding, especially any bleeding or spotting after menopause. ^{[3] [4]} While advanced gynecologic cancers can sometimes lead to urinary symptoms, hematuria by itself is not a typical presenting sign of endometrial cancer, and vaginal bleeding should be distinguished from blood coming from the urinary tract. ^{[5] [6]}

How endometrial cancer usually presents

• The most common sign is abnormal uterine/vaginal bleeding for example, bleeding between periods, unusually heavy or prolonged bleeding after age 40, or any bleeding/spotting after menopause. ^{[7] [3]}
• Because this symptom is so frequent, any postmenopausal bleeding should prompt medical evaluation to rule out uterine causes, including endometrial cancer. ^{[6] [8]}
• There is currently no effective general-population screening test for endometrial cancer; diagnosis starts with evaluation of abnormal bleeding (often with endometrial sampling and/or transvaginal ultrasound). ^{[7] [5]}

Common causes of visible blood in urine

• Urinary tract infection (UTI): Burning with urination, urgency, frequency; kidney infection adds fever or back/side pain. ^{[2] [1]}
• Stones (kidney or bladder): Can cause pain and hematuria when minerals crystallize and form stones. ^{[2] [1]}
• Exercise, medications, or menstruation can also cause red urine without a serious problem. ^[1]
• Cancers of the urinary tract (e.g., bladder, kidney): Especially in adults with risk factors; blood in urine can be the first sign. ^[1]
• Even small amounts of blood warrant attention because hematuria can sometimes signal significant disease. ^{[9] [10]}

When to see a doctor

• You should seek medical care any time urine appears pink, red, or cola-colored (suspected blood), even if it’s painless. ^[11]
• You should also see a clinician promptly for any vaginal bleeding after 12 months without periods (menopause), even light spotting. ^{[6] [8]}
• If you’re unsure whether the blood is from the urine or the vagina/uterus, a clinician can help distinguish the source with a pelvic exam and urine testing. It’s important to identify where the bleeding originates. ^{[6] [5]}

How to tell urinary bleeding from vaginal bleeding

• Red or pink urine without vaginal spotting often points to hematuria. A simple urine test can confirm red blood cells in urine. ^{[11] [12]}
• Vaginal bleeding is noticed on wiping or as spotting/flow from the vagina; postmenopausal spotting strongly suggests a gynecologic source and needs evaluation for uterine, cervical, or vaginal causes. ^{[6] [8]}
• Clinicians commonly perform a urinalysis, pelvic exam, and, if needed, imaging (for urinary causes) or transvaginal ultrasound and endometrial sampling (for uterine causes). ^{[12] [13]}

What to expect during evaluation

• For hematuria: your clinician may ask when the blood appears during urination, presence of clots, pain, and infection symptoms, then order urinalysis, urine culture, and imaging if indicated. ^[12]
• For postmenopausal or abnormal uterine bleeding: first-line tests are transvaginal ultrasound to assess endometrial thickness and endometrial biopsy to check for abnormal cells; these steps diagnose or rule out endometrial cancer. ^{[13] [5]}

Red flags that need urgent care

• Blood in urine plus fever, back/flank pain, or severe abdominal pain (possible kidney infection or stone). ^[2]
• Large blood clots in urine, inability to urinate, severe weakness, or dizziness. ^[11]
• Any postmenopausal bleeding or heavy/ongoing bleeding at any age. ^{[6] [7]}

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Quick reference: Hematuria vs. endometrial cancer symptoms

Feature	More suggestive of urinary cause	More suggestive of endometrial/uterine cause
Primary symptom	Pink/red/cola-colored urine, may be painless	Vaginal spotting/bleeding (especially after menopause)
Common triggers/causes	UTI, stones, exercise, medications	Hormonal/endometrial changes; postmenopausal bleeding
Typical associated signs	Burning to urinate, urgency, flank pain, fever (kidney infection)	Pelvic cramping, abnormal uterine bleeding patterns
First tests	Urinalysis, urine culture, possible imaging	Transvaginal ultrasound, endometrial biopsy
Urgency	Visible hematuria should always be evaluated	Any postmenopausal bleeding needs prompt evaluation

Visible hematuria should be assessed because causes range from benign to serious, but it is more commonly due to urinary conditions than to endometrial cancer. ^{[1] [2]} Conversely, abnormal uterine/vaginal bleeding especially after menopause is the classic early sign of endometrial cancer and should be evaluated promptly. ^{[6] [4]}