Modeling the Potential Benefit of an Over-the-Counter Progestin-Only Pill in Preventing Unintended Pregnancies in the US
Authors: Guillard Hélène , Laurora Irene , Sober Stephanie , Karapet Artin , Brass Eric P. , Glasier Anna 
Published: March 2023

Approximately 50% of the 6.1 million annual pregnancies in the United States are unintended. Despite widespread public knowledge of contraception, many barriers exist to access including prescription requirements. There has been support backed by peer-reviewed studies from major medical organizations to have a progestin-only pill (POP) available as an over-the-counter (OTC) medication. A recent actual-use clinical trial simulating the OTC use of a POP (norgestrel) over a 6-month period provided important data on the distribution of different contraceptive methods among potential OTC POP users.

This model aimed to use data on the baseline distribution of different contraceptive methods from the actual-use trial to analyze the potential impact of the use of an OTC POP on the number of unintended pregnancies in the United States. This trial included 883 women that used the norgestrel 0.075 mg POP over a 6-month period. In the model, estimates were normalized to a population of 100,000 women, and the number of pregnancies expected among 2 hypothetical cohorts were compared using different contraceptive methods over 1 year. The first cohort consisted of women with contraceptive methods based on that of the volunteers entering the actual-use trial, and the second was women exclusively using an OTC POP as their contraception. A tipping-point analysis was conducted to determine the failure rate of the OTC POP beyond which no unintended pregnancies would be prevented by OTC POP use compared with the actual-use cohort before enrollment. Several sensitivity analyses were conducted, including the actual-use cohort distribution before enrollment being replaced with the contraceptive distribution reported in the 2017 to 2019 data from the US National Survey of Family Growth, capturing a higher percentage of users of the most effective methods and lower percentage of users of no method.

A total of 37,624 unintended pregnancies were expected if 100,000 women continued their current contraceptive method mix assuming a “no method” failure rate of 85%. A total of 7000 unintended pregnancies were expected if 100,000 women used the OTC POP (7% failure rate) exclusively. When comparing the 2, over 80% and an estimated 30,624 unintended pregnancies would be prevented over 1 year using an OTC POP compared with a use profile based on methods use before enrollment in the actual-use trial. Sensitivity analyses altered the expected number of unintended pregnancies, but in each scenario, the overall number of expected pregnancies remained lower among the OTC POP cohort. The tipping point analysis revealed that the failure rate of OTC POPs beyond which there would be no further reduction in unintended pregnancies is 38%, decreasing to 12% with more conservative model inputs.

The results of this study show that using data from an actual-use clinical trial, among 2 modeled cohorts of women using either a POP or a mix of contraceptives based on real clinical use patterns, there is a significant reduction in unintended pregnancy using an OTC POP. The model described here suggests that use of an OTC POP would result in a clinically meaningful reduction in unintended pregnancies in the United States.