When used properly, oral contraceptives are extremely effective in preventing unintended pregnancies, yielding only 3 pregnancies per 1000 users in the first year of use. In reality, however, women may not be as adherent as necessary to obtain this ideal rate-studies have shown that about 50% of women regularly miss at least 1 pill per cycle.
When used properly, oral contraceptives are extremely effective in preventing unintended pregnancies, yielding only 3 pregnancies per 1000 users in the first year of use. In reality, however, women may not be as adherent as necessary to obtain this ideal rate-studies have shown that about 50% of women regularly miss at least 1 pill per cycle. As a result, a higher pregnancy rate of 80 per 1000 can be seen. Meanwhile, research has demonstrated that women are more adherent and have less unintended pregnancies when they receive larger amounts of contraceptive pills (ie, enough to cover multiple cycles). Dr Diana Greene Foster, associate professor in the department of obstetrics and gynecology and reproductive sciences at the Bixby Center for Global Reproductive Health at the University of California San Francisco, and colleagues sought to determine how the number of oral contraceptive pill packages dispensed relates to subsequent pregnancies and abortions.
Foster and co-investigators conducted a retrospective review of 84,401 women who received oral contraceptive pills in January 2006 through California’s Family Planning, Access, Care and Treatment (PACT), a Medicaid family planning waiver program that provides contraceptives at no cost to women at risk for pregnancy with incomes up to 200% of the federal poverty level. Most women received a 3-pack of pills per visit (Figure 1). Older women (≥ 40 years) were least likely to receive a year’s worth of pills (4%; a year’s worth of pills was defined as 12 to 13 packs dispensed) while young women (< 20 years old) were most likely to receive a year’s worth of pills (18%).
Race also seemed to play a role in who received a year’s worth of pills, with Asians and white non-Latina women (20% and 19%, respectively) most likely to receive such and Spanish-speaking Latinas least likely to receive a year’s worth of pills (3%). The researchers noted that 24% of the women filled their prescriptions at pharmacies, where a 3-month supply was the maximum allowed. Only one third of the women received their medications from clinics that allow dispensing a year’s worth of medication; however, only one third of those patients (34%) actually received a year’s worth of pills.
Figure 1. Breakdown of pill packs dispensed.
The researchers then linked this data with Medi-Cal data for 397,187 women with a pregnancy event (ie, birth, miscarriage, abortion, or ectopic pregnancy) between January 2006 and January 2007. Based on the data, Foster and colleagues estimated that 2.8% of the women who received contraceptive pills in January 2006 had a pregnancy event later that year. As anticipated, women who received the 1-year supply of pills were least likely to experience a pregnancy event (Figure 2). After conducting a multivariate analysis, the researchers found that the 1-year supply was associated with a 30% reduction in the odds of conceiving a pregnancy in the subsequent year and a 46% reduction in the odds of an abortion.
Figure 2.Number of pregnancies based on amount of pills received.
Why might the 1-year supply result in less unintended pregnancies? Foster and colleagues hypothesize a number of reasons, including the obvious ease of accessibility and less time/inconveniences associated with having the supply on hand. They also postulate that each time a woman must seek another pill pack it might open the door to reconsidering continuation of use. Further, they believe it is possible that women might assume the pill is safer to use when they are given such a large quantity of the medication.
In a comment to the press, Foster explained, “Women need to have contraceptives on hand so that their use is as automatic as using safety devices in cars. Providing one cycle of oral contraceptives at a time is similar to asking people to visit a clinic or pharmacy to renew their seatbelts each month.”
Overall, Foster and colleagues believe this study provides further evidence for providing longer term supplies of contraceptive pills for patients. They wrote: “If all 65,000 women who received only one or three packs of pills experienced the same pregnancy and abortion rates as women who received a 1-year supply, then almost 1,300 publicly funded pregnancies and 300 abortions would have been averted.”