Modeling the potential benefit of an over-the-counter progestin-only pill in preventing unintended pregnancies in the U.S.

Abstract

To develop a model to estimate the possible impact of use of an over-the-counter (OTC) progestin-only pill (POP) on the number of unintended pregnancies in the United States. Using typical use failure rates (7% for POPs), we compared the expected number of unintended pregnancies for two theoretical cohorts of 100,000 women: one which purchased and used an OTC POP exclusively for contraception, the other using contraceptive methods at proportions obtained from an actual-use clinical trial simulating OTC use of norgestrel 0.075 mg (including 35% using no method and only 19% using hormonal contraception or long-acting contraceptives). Sensitivity analyses were conducted using alternative model inputs such as different failure rates for OTC POPs and varied alternative contraceptive method mix. An estimated 37,624 unintended pregnancies would occur annually if 100,000 women continued their usual contraceptive method as used at baseline in the actual use trial. This would be reduced by 81% to 7,000 pregnancies with the exclusive use of an OTC POP - a net reduction of 30,624 unintended pregnancies annually. While the number of unintended pregnancies prevented varied as the model parameters were modified (ranging from 1,461 to 34,124), a net benefit of OTC POP use was observed over a wide range of input values. Using data from a real-world contraception user profile, our model suggests that use of an OTC POP could reduce the overall number of unintended pregnancies in the United States. This conclusion remains true across a wide range of modeled scenarios. The estimates suggested by this model are supportive of an OTC switch for a POP.