JAMA : the journal of the American Medical Association
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Many women spend a substantial proportion of their lives preventing or planning for pregnancy, and approximately 87% of US women use contraception during their lifetime. ⋯ Oral contraceptive pills are the most commonly used reversible contraceptives, intrauterine devices and subdermal implants have the highest effectiveness, and progestin-only and nonhormonal methods have the lowest risks. Optimal contraceptive selection incorporates patient values and preferences.