The birth control patch is a weekly hormonal patch worn on the skin that releases estrogen and progestin to help prevent pregnancy. It is about 93% effective with typical use, meaning about 7 out of 100 people may become pregnant in a year, and about 99% effective with perfect use. Many people choose it because it does not require taking a daily pill and can also help make periods more regular, lighter, or less painful. It is usually changed once a week for 3 weeks, followed by 1 patch-free week, although some people use it differently under clinician guidance. The patch can be convenient, but it may be visible on the skin and can sometimes cause skin irritation, nausea, breast tenderness, or spotting.