Im 39 weeks pregnant and had blood in my urine. got it checked with urinanalysis and it showed no infection. the blood went away. now 2 days later it came back. what could be causing this?

Could be: Vaginal spotting like the beginning of your show. Might go into labor at any time. Enjoy that baby!

Microscopic heme: Microscopic hematuria at the end of a pregnancy can be a normal variant as the uterine lining and cervix starts to change in preparation for the birth process. No infection is good, and this will simply be followed up after your pregnancy to assure full resolution. Best wishes.

Unclear, but...: You're blessed non-uti-related gross bloody urine happens at the time of 39 pregnancy and be ready to be a mother. At this time, just focus on baby delivery and home-coming as long as no possible unbearable symptoms related with bloody urine, and do nothing now. But after post-delivery recovery, need to be evaluate with ct of urinary tract ; cystoscopy for making sure you have no stone, or others.