The mini-pill is a common name for the progestin-only birth control pill. (As opposed to normal birth control pills that contain a combination of progestin and estrogen).

The mini-pill is generally prescribed for women who have had previous estrogen-related problems with the combination pill, such as severe migrane headaches, weight gain, or blood clots. Since smokers are especially prone to estrogen-related blood clots, the mini-pill may be a good option for them.

There are several key ways in which the progestin-only pill differs from standard birth control pills:

  • Progestin-only pills may not prevent ovulation as effectively as combination pills. However, they do have the benefit of thickening cervical mucus, preventing sperm from entering the uterus.
  • The mini-pill has a 95% success rate (with perfect use), slightly lower than the 98% success rate of combination pills.
  • The main side effect of the mini-pill is mid-cycle bleeding or spotting.
  • There are no placebo pills. The mini-pill is taken in its full dosage for the entire menstrual cycle.
  • The effectiveness of the progestin-only pill is highly dependent on consistent use. Delaying taking the pill by even as little as 3 hours beyond the normal time can greatly increase the risk of pregnancy.