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How Effective Are Progestin-Only Birth Control Pills?

Progestin is the synthetic form of progesterone used in combination and progestin-only birth control pills. Progestin-only pills, sometimes referred to as POP or mini-pills, have “about the same effectiveness as combination estrogen and progestin pills, rings, and patches,” which are up to 99.9% effective, according to The American College of Obstetricians and Gynecologists. To maximize efficacy:

  • Take the pill at the same time daily.
  • Start your initial pack on the first day of your period or the first Sunday after it begins.
  • Start your next pack of pills the day after you finish a pack.

When you first start taking progestin-only pills, such as Errin or Camila, take the first pill on the first day of your period.

If your pill cycle falls out of balance, even something as minor as taking the pill three or four hours after the normal time, use an alternative form of birth control or abstain from sex for at least 48 hours. If you’ve had sex during this time without alternative protection, emergency contraception is an option.

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