"The Pill" is an oral contraceptive method that prevents pregnancy. There are many types of birth control pill options: Some can help with PMDD and menstrual cramps, some are safe for breastfeeding mothers, and some only allow you to have a few periods a year. You should talk to your doctor to decide which type is best for you. Birth control pills can have side effects such as weight gain and nausea, so you should discuss these with your doctor as well. Follow the links below to find WebMD's comprehensive coverage about how birth control pills work, what types are available, and what the side effects are.