Hi. Welcome to healthcaremagic community forum.
RBC's stands for Red blood cells, the main component of blood cells. More the number of RBC's in the urine visualised under high power field(HPF) microscope, higher the amount of blood in urine. Presence of more than 4 RBC's/HPF without visible blood in the urine is a condition termed as microscopic hematuria
Microscopic hematuria, the cause are variable and needs a battery of tests for diagnosing. Inspite of the all tests, about 20% individuals who have this conditions, a cause is not known. One of the probably reasons being episode of bleeding.
Since you recently had your periods/abortion
(before the tests were done), its possible that the blood that is seen is due it.
Hence my suggestions are get a repeat test after 2 weeks after your period.
If blood is also noticed, then consider getting the other tests done.
Discuss with your doctor - gynaecologist or urologist
who will be able to suggest you the tests depending on the physical examination findings.
Hope this message was useful to you. Get back to this forum, if you need any more suggestions