Contraceptive pills are medications taken by women to prevent pregnancy. They usually contain hormones, such as estrogen and progestin, which work by stopping ovulation, thickening cervical mucus, and thinning the uterine lining. When taken correctly, these pills can be over 99% effective in preventing pregnancy. In addition to preventing pregnancy, contraceptive pills can also help regulate menstrual cycles, reduce menstrual cramps, and treat conditions like polycystic ovary syndrome (PCOS) and acne. It's important for women to consult with a healthcare provider to choose the right type of pill and understand potential side effects.