Microscopic hematuria can be due to
urinary tract (bladder)
infection, swelling in the filtering system of the kidneys, stone in bladder or in a kidney, blood disease, like sickle cell anemia, certain medicines and tumors in the urinary tract.
You may need a series of investigations like urine examination, urine culture, ultrasound or cystoscopy to confirm the diagnosis. Please consult a urologist and get it done.
I sincerely hope that helps. Take care and regards.