What to do if i cannot take birth control because of medical reasons. what is the safest method / combination of methods that best protects against pregnancy?

IUD or Tubal: It depends on what your medical problems are. With some medical problems you can still take progesterone only birth control method such as Depo Provera. If you can't take any hormones at all, I would recommend getting a tubal ligation or a Paragard IUD. Other options would be barrier methods such as condoms, a diaphragm or Today Sponge. Best wishes!