I have est/prog + breast cancer fixing to start chemo. what is a recommended birth control?

Paragard IUD: In your case, i would choose a birth control method completely without any hormones until you have finished with your cancer treatment. I recommend the paragard iud. It is extremely effective. The main side effect for most of my patients is heavier menstrual bleeding and some spotting as well. Good luck with your cancer treatment!

Condoms: The chemotherapy itself will probably turn your ovaries off, either temporarily or permanently, but it is too variable to know for sure. You should not add birth control pills or Progesterone iud during chemo for an estrogen sensitive cancer. Therefore, your best choices are condoms or a copper iud.

Anything But BCPs: Since your cancer is estrogen-sensitive, you should never use birth control pills. Furthermore, your oncologist will be prescribing tamoxifen after you complete ctx and rtx, which can cause birth defects. Therefore, you need an effective, non hormonal birth control option. Please discuss all options with your ob. Btw-have you had brca testing? At your age, this is advisable. Good luck!