Understanding Blood in Urine During Pregnancy: Causes & Next Steps

Question
I am 22, female, 3 months pregnant with my second child.  During a routine urinalysis with my OB they found RBC's and a trace of blood in my urine but the culture for bacteria was negative.  She put me on antibiotics and told me she would check it again next month.  I have recurrent bladder infections, but what are some of the other causes for RBC's and blood in urine.  Thank you

Answer
Hi Amy,
There are times when answering a question is not appropriate. To name all of the causes for blood in the urine would only serve to unnecessarily worry you. Given the description, I would agree with your OB. It is probably related to your chronic cystitis. If the doctor suspected anything other than this, I'm sure s/he would look into it. I hope you understand my reasoning.