Hormonal contraceptives

Hormonal contraceptives use an estrogen, a progestin, or both to prevent pregnancy, mainly by stopping ovulation and thickening cervical mucus. Combined pills such as levonorgestrel and ethinyl estradiol are taken daily, and other forms include patches, vaginal rings, injections, implants, and intrauterine devices. Nausea, breast tenderness, headache, and irregular bleeding are common, especially in the first few months. Products containing estrogen raise the risk of blood clots, heart attack, and stroke, especially in women over 35 who smoke, and some drugs that speed up liver enzymes can make them less effective.

• Levonorgestrel-ethinyl estradiol