Using Progestin-Only Pills Correctly

Progestin-only oral contraceptive pills (POPs) have specific advantages over combined oral contraceptives. Because they do not contain estrogen, they are a good contraceptive choice for breastfeeding women and for women with health conditions that preclude use of combined oral contraceptives (containing both estrogen and progestin). Yet POPs are not as well known or as frequently used as the combined estrogen-progestin oral contraceptives. Only one to ten percent of the oral contraceptives sold are POPs. They can be an increasingly valuable part of any family planning program, if providers are well informed about POP characteristics and make sure that their clients know how to take pills correctly.

Progestin-only oral contraceptives have very low doses of progestin, lower than combined pills. POPs prevent pregnancy in two main ways:

• They prevent ovulation in about half the cycles.
• They cause a thickening of the cervical mucus, which prevents sperm from reaching the egg.

POPs also produce changes in the endometrium so that it becomes less receptive to implantation in the unlikely case that ovulation occurs, and POPs slow the movement of the egg through the fallopian tube.

These multiple mechanisms of action, along with the low doses of progestin required, create most of the advantages, and the few disadvantages, of POPs.

POPs are indicated most strongly for women who prefer oral contraceptives but should not be taking estrogens.

They are especially recommended for:

• breastfeeding mothers;
• women over age 35, including smokers;
• women with hypertension (high blood pressure).

POPs may also be recommended for women with:

• migraine (vascular) headaches;
• thromboembolism;
• cardiovascular disease;
• diabetes;
• sickle cell disease.

Like all progestin-only methods, POPs do not have most of the estrogen-related side effects of oral contraception. For example, the nausea, headaches and other symptoms associated with starting the combined pill are minimal. Side effects of POPs are few. Menstrual irregularities, especially more frequent bleeding, are the most commonly reported side effects. Informing women of this possibility will help allay concerns if such problems develop.

Once POPs are discontinued, fertility returns rapidly. Unlike other progestin-only methods (especially injectables and implants), POPs are inexpensive and user controlled at all times. They can be bought over-the-counter in many countries.

Only three categories of women should not use POPs. These include women with:

• a known or suspected pregnancy (as for any drug);
• known or suspected breast cancer;
• undiagnosed abnormal genital bleeding, which could indicate a reproductive tract cancer (or other conditions requiring medical care).

POPs must be taken every day, without interruption for bleeding. When a woman takes POPs, her progestin levels build up rapidly after taking a pill, then return to baseline levels in 24 hours. Therefore, POPs should be taken at the same time every day. If a POP is taken three or more hours late, a back-up method of contraception, such as the condom, is needed until 48 hours after pill-taking resumes. Although this means a back-up method may be needed more often for POPs than for combined pills, it is only needed for two days, not seven days as for combined pills.

Ectopic pregnancies, while rare, are more likely to occur among POP users than among women using other contraceptive methods. Symptoms include abdominal pain and amenorrhea.

Specific drugs that may interfere with POPs effectiveness include most anticonvulsants and rifampicin, used primarily to treat tuberculosis.
POPs offer no protection against HIV/AIDS and sexually transmitted infections (STIs). Therefore, women at risk for AIDS and STIs should consider the use of latex condoms.

POPs can be a good contraceptive choice for breastfeeding mothers who wish to use hormonal contraception. Progestins administered alone do not interfere with breastmilk production. Also, because such small amounts enter the infant's system (resulting in infant plasma levels of 1 to 6% of the levels in maternal plasma), no adverse effects on the health, growth or development of the infant have been found.

In addition, breastfeeding mothers have less need for back-up contraceptive methods. Women who are fully breastfeeding already have the back-up protection of their breastfeeding and, therefore, do not need to use a second back-up method when a single pill is taken late.

POPs are a safe, effective method of contraception. When discussing contraception, providers should inform clients of the special advantages of POPs, including safety for breastfeeding mothers and women who want hormonal contraception but cannot take combined pills. Because these pills must be taken at the same time each day to be effective, counselling clients about correct use is especially important.

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