When taken properly, the pill is a highly effective contraceptive. Oral contraceptives are unique among family planning methods, however: Their full effectiveness requires the user's daily action. In part because some women have trouble taking the pill correctly, pregnancy rates are usually much higher than if the pill were used perfectly.

For combined OCs the perfect-use pregnancy rate is estimated at only 0.1 per 100 women in the first 12 months of use. In actual use pregnancy rates range from 1.7 to 10.5 pregnancies per 100 women in the first 12 months in 21 surveyed countries.

Better pill use would make a big difference. Based on worldwide levels of pill use in 2000, for example, over 2 million women become pregnant unintentionally each year because they do not take the pill effectively. Also, women would be healthier, and medical costs would be less, since complications of pregnancy, childbirth, and unsafe abortion are among the leading causes of women's ill health and death in developing countries.

Encouraging more effective OC use requires understanding problems with pill-taking. OC users make a variety of mistakes. These include missing pills, taking “rests” from pill use, starting the next pill pack too late, and taking pills out of sequence. Research suggests that most pregnancies during pill use result from increasing the number of days between pill packets that hormonal pills are not taken. Errors sometimes occur because women are not told how to use the pill, or they receive incorrect advice. Some users do not understand or remember instructions.

Some pill users who become pregnant report vomiting or diarrhea and/or use of antibiotics around the time of conception. It is not clear what role these events play in pill failure.

Using mass media. Radio, television, and other mass media can inform potential users, users, and their partners about the pill and other methods. The mass media often start people thinking about family planning and contraceptives. They also can remind continuing users about effective pill use and help to counter false rumors about the pill.

Counseling. Counseling—face-to-face dialogue between client and provider—improves OC use. Women who receive good counseling are more likely to continue using the pill and to use it effectively. In particular, women need to know about the common side effects before they start the pill. Counseling is especially helpful both when a client is deciding about the pill and if she experiences side effects in the first months of use. Providers counsel better when trained and enabled to use both knowledge of family planning and communication skills.

New guidelines, new attitudes. Family planning programs help clients use OCs more successfully when they update guidelines and procedures to reflect new scientific understanding about OCs. Unnecessary legal, medical, or other institutional barriers sometimes impede pill use. Such barriers include baseless eligibility restrictions, unnecessary screening procedures, and legal, programmatic, and provider bias against certain family planning methods or groups of clients. By adopting guidelines, procedures, and attitudes that respond, first and foremost, to clients' needs and wishes, family planning programs can help pill users find more satisfaction and more value in their contraceptive method.

Improving access. Making it easier to obtain OCs helps women use them correctly without interruption. Ensuring regular supplies, making pills affordable, and offering them conveniently all are important. Without good access, women may discontinue, take pills inconsistently, or switch to less effective methods. Convenient clinics, community-based distribution, social marketing, links with other health services, and good supply chains can make it easier for women to use the pill.