Chances of getting pregnant while on the pill?

Yasmin is 99% effective when taken effectively, which is pretty much the best you're going to get. So it's safe to have unprotected with your partner. Obviously if you do want to be extra safe you could use condoms too but personally I wouldn't think there's much need seeing as you're in a long term relationship. And seeing as you're taking the pill properly then you should be fine (: but obviously if you are sick at some point because of alcohol or any reason at all, make sure you use a condom if you have in the following week.