Hello and welcome to HCM.
Thank you for your query.
The first step would be to find where exactly the bleed is coming from. Whether from the
ureter, the vagina or surrounding structures. Once we find the exact source, we can concentrate on that region and find the cause.
A sign of spotting or bleeding which has never occurred previously in a woman with an otherwise regular menstrual cycle could be due to various reasons (eg. infections, etc.). Which is why, I would advise you to visit your doctor and get physically examined at the earliest. Are you sexually active or do you have other symptoms like:
-Burning sensation while urinating
-Frequent urination
-Increased urge to urinate, but less amount of urine passed
-Chills
-Fever
-Lower abdominal and/or flank region pain
-Itching around the genitals
-Blood in urine or immediately after (not always seen)
These are all symptoms of an infection and will help in further diagnosing your condition with ease. Either way, kindly visit your doctor to help find the cause.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications at: http://doctor.healthcaremagic.com/doctors/dr-shoaib-khan/64581 . I would gladly help you.
Best wishes.