Background: Almost 12 million U.S. women use oral contraceptive (OC) pills as their primary method of birth control, but up to 8 percent are estimated to experience a contraceptive failure in their first year. Breaks in continuity of supply of OCs (“running out of pills” for any reason) was one of the top three reasons for contraceptive failure in a small study; however, this topic has not been extensively studied. Most women are provided with a 30-day supply, requiring monthly refilling of OC prescriptions. In addition, many health plans restrict medications to a 30-day supply on a single prescription. Foster and colleagues studied the implications of providing one year's supply (13 cycles) at a contraceptive consultation.

The Study: The authors studied data from a program that provides reproductive health services to more than 1.5 million low-income California residents per year. The program provided OCs to 82,319 women in January 2003. For these women, the researchers monitored use of services such as physician office visits, testing for sexually transmitted infections, pregnancy tests, and Papanicolaou (Pap) screening throughout 2003. Financial and demographic information was also gathered on participants. Most women (63 percent) were prescribed three cycles of OCs at the initial study contraceptive visit, but 16 percent were prescribed one cycle and 7 percent received prescriptions for 13 cycles. Teenagers were twice as likely as women in their 30s and 40s to receive 13 cycles (8 compared with 4 and 3 percent, respectively). The rates of prescribing 13 cycles also varied significantly by race, with 4 percent for black women, 8 percent for Hispanic women, and 12 percent for white women. New patients were twice as likely to be prescribed 13 cycles as established patients (12 compared with 6 percent).

Results: Women who received prescriptions for 13 cycles were significantly more likely to still be receiving OCs 15 months after the initial prescription. At the 15-month follow-up, 43 percent of women who received prescriptions for 13 cycles had obtained sufficient pills for at least one year of continuous use compared with 22 percent of women given prescriptions for three months and 20 percent of those initially prescribed one month's supply. The rates of pill wastage were higher in women prescribed 13 cycles than in those prescribed three cycles (6.5 percent of cycles dispensed wasted compared with 2.0 percent), but the women initially prescribed 13 cycles completed an average of 14.5 cycles during the study compared with 9.0 cycles completed by women initially prescribed three months' supply. Despite having significantly fewer physician visits, a significantly higher percentage of women prescribed 13 cycles had Pap smears and chlamydia tests during the study. The program calculated an average saving of about $99 per patient for women prescribed 13 cycles compared with those prescribed three cycles (see accompanying table).

Conclusion: The authors conclude that prescribing a one-year supply of OCs contributes to more continuous use and lower costs than limiting prescriptions to a three-month or a one-month supply.