Thanks for your query.
IUD and IUS have NO EFFECT on fibroadenomas, unless they are progesterone
Progesterone pills and IUD is generally NOT recommended for women already having breast lumps.
Regarding future pregnancies, pills are quite safe, but IUD s might sometimes cause pelvic infection
You can try using condoms, as that is the best contraception
If not compliant with condoms, try using low dose estrogen
pills, and stay on regular follow up for the fibroadenoma.
All the best.