What is the Minipill?

The minipill is another type of oral contraceptive. Although taken daily like combined oral contraceptives, minipills contain only the hormone progestin and no estrogen. They work by reducing and thickening cervical mucus to prevent sperm from reaching the egg. They also keep the uterine lining from thickening, which prevents a fertilized egg from implanting in the uterus. These pills are slightly less effective than combined oral contraceptives.

Minipills can decrease menstrual bleeding and cramps, as well as the risk of endometrial and ovarian cancer and pelvic inflammatory disease.

Because they contain no estrogen, minipills don't present the risk of blood clots associated with estrogen in combined pills. They are a good option for women who can't take estrogen because they are breastfeeding, because estrogen-containing products cause them to have severe headaches or high blood pressure, or for other reasons.

Side effects of minipills include menstrual cycle changes, weight gain, and breast tenderness.

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Adapted from the United States Office on Women's Health in the Department of Health and Human Services.