I want to take birth control pills for b.c. & the relief of bad PMS. I donated my kidney just under a year ago & have below or avg BP. Is it safe?

Yes. In fact, taking BCP's to help to control your PMS symptoms is probably better for the health of your 1 kidney, than taking excessive amounts of OTC meds. like Ibuprofen or Naproxen. Just need to monitor your B.P. response to BCP's. If your B.P. remains fine, then no worries. Best of luck.