Birth control while on carbimazole

Is anyone else here on carbimazole for hyperthyroidism/Graves' disease? Because that drug can cause birth defects etc if taken while pregnant, my doctor has recommended that I use the contraceptive pill while on carbimazole since it's highly effective. I'm happy to delay pregnancy while on this drug, but I don't want to use the contraceptive pill. My husband and I would prefer to just keep using condoms, but my doctor is worried that they aren't effective enough - there would be a higher risk that I get pregnant by accident and then the baby is harmed because of the carbimazole. I'm not sure if this is good advice or just my doctor wanting to be extra extra careful. Is anyone else on carbimazole or a similar thyroid suppressant? What type of birth control do you use?