Thanks for the query.
The possible causes are:
-Local causes like cervical polyp
or erosion etc.
can lead to blood stained urine.
So you once consult gynecologist, get examined, go for ultrasound
and urine microscopy with this the possible cause for your problem can be identified and treatment can be given accordingly.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429