Def be safe. Some girls do get weigh after taking the pill, unfortunatly it happens. Sometimes mood swing are some side effects also. But there is a new thing in the market. Its not so new, but its a shot you take every 3 months. I don't know what the side effects are, but I do know some girls don't get there periods at all after taking this shot. There are many options to be safe, if this issue is a major concern, talk to your doc/ or not have sex/or cap that sucker!