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Choosing a Birth Control Method

(Published September 2011)

Progestin-Only Oral Contraceptives

Description

Two formulations are available: one contains 0.35 mg of norethindrone, the other contains 0.075 mg of norgestrel. The primary mechanism of action is thickening of the cervical mucus.

Use

The efficacy of progestin-only pills is highly dependent on consistent use; it is critical that women take the pill at the same time (i.e., within 3 hours) every day. There is no placebo week with progestin-only pills.

Progestin-only Contraceptive Pills

Effectiveness

Often called "mini-pills," progestin-only pills are a good contraceptive choice for women who cannot use estrogen.59

This method is highly effective, with a failure rate of 0.3 percent with perfect use and 9 percent with typical use.18

Risks

None.

Side Effects

  • The primary side effect of progestin-only oral contraceptives is irregular menstrual bleeding—spotting or breakthrough bleeding, amenorrhea, or shortened cycles.
  • Irregular bleeding decreases in many users by cycle 12.
  • Less common side effects include headache, breast tenderness, and dizziness.

Contraindications and Precautions

Medical Eligibility Criteria for Progestin-only Pills

Category 4

(unacceptable health risk if the contraceptive method is used)

  • Current breast cancer

Category 3

(theoretical or proven risks usually outweigh the advantages of using the method)

  • History of bariatric surgery with a malabsorptive procedure (e.g., gastric bypass)
  • Ischemic heart disease or stroke (current or history of)—for continuing method
  • SLE (positive for antiphospholipid antibodies or status unknown)
  • Migraine with aura—for continuing method (i.e., if migraines worsen in a woman who is already using progestin-only pills)
  • Breast cancer in the past; no evidence of disease for 5 years
  • Severe cirrhosis
  • Malignant liver tumor
  • Certain antiretroviral and anticonvulsant medications (some are designated category 2)
  • Rifampin or rifabutin therapy

Source: Reference 5

Advantages

  • Discreet
  • Effective
  • Rapidly reversible
  • Easy to use, start, and stop
  • No associated nausea
  • Lack of estrogen in progestin-only pills makes the method appropriate for smokers older than age 35, postpartum breastfeeding women, and others with contraindications to estrogen
  • Provides protection against uterine and ovarian cancer, benign breast disease, PID

Disadvantages

  • Requires a prescription
  • Adherence can be challenging; user must remember to take pill at same time daily
  • Initial irregular bleeding
  • No protection against STIs

Counseling Messages

  • The progestin-only pill must be taken at the same time each day.
  • If a pill is more than 3 hours late, a back-up method of contraception should be used for at least the next 48 hours.
  • Patients using progestin-only pills should obtain emergency contraception in advance. (Note that patients who are less than 17 years old will need a prescription for EC.)
  • A range of bleeding disturbances may occur with progestin-only pills—from amenorrhea to irregular, frequent, or prolonged bleeding.
  • The irregular bleeding pattern is likely to improve within a few months of pill initiation.
  • If bleeding is heavy or particularly bothersome, women should contact their health care provider.
  • This method does not protect against STIs.