What Are Period Pills?

By Rebecca H. Allen, MD, MPH, Editor

Synopsis: In this national survey of almost 7,000 people aged 15 to 49 years who were assigned female sex at birth, conducted between December 2021 and January 2022, one-quarter of participants (24%; 95% confidence interval [CI], 22%, 25%) stated that they would personally use period pills and about half of the respondents (52%; 95% CI, 50%, 53%) were in favor of the availability of period pills.

Source: Upadhyay UD, Sietstra C, Koenig L, et al. Interest in period pills in the United States: A nationally representative survey, 2021-2022. Contraception. 2025; Jun 5. doi: 10.1016/j.contraception.2025.110980. [Online ahead of print].

Pills taken to cause menstrual bleeding when a period is considered late and pregnancy is suspected but not confirmed are called “period pills,” “late period pills,” or “missed period pills.” They consist of mifepristone with misoprostol or misoprostol alone. The authors of this study sought to estimate interest in period pills in the United States because, traditionally, they have more commonly been used in international settings.

This was a national cross-sectional survey of United States residents who were members of a market research firm’s Knowledge Panel between December 2021 and January 2022. The participants, assigned female at birth, were selected by probability-based sampling and could take the survey in English or Spanish. The sample was weighted to produce a nationally representative estimate. The survey was created by the University of California San Francisco research team and included questions regarding obstetric history, sexual orientation, barriers to reproductive care, attitudes toward abortion, and interest in period pills after their purpose was described. The survey also asked questions about the potential pros and cons of using period pills. Demographic data came from the market research firm. The primary outcome included whether participants would consider using period pills and were in favor of period pills being available. The outcomes then were analyzed by patient characteristics.

There were 16,113 panel members and 7,016 (44%) agreed to participate in the survey. Fifty-two participants were excluded for not providing answers to the outcome questions, leaving 6,964 participants for analysis. The sample was diverse, with 15% Black, 15% Mexican, 5% multiracial, and 15% who were born outside the United States. A total of 24% (95% confidence interval [CI], 22%, 25%) of the sample stated they would definitely or probably use period pills.

Factors associated with period pill use included age 18-29 years; never married, widowed, or divorced; higher education; previous abortion; non-heterosexual orientation; and had faced a barrier accessing reproductive healthcare in the past three years. Lower levels of interest were associated with being foreign-born, Christian, and living below the federal poverty level.

For the other primary outcome, 52% (95% CI, 50%, 53%) of respondents said they were somewhat or strongly interested in having period pills available for others. In terms of the advantages and disadvantages of period pills, the most common advantage cited was the ability to stop a pregnancy prior to needing an abortion and the privacy around abortion that it offered, as well as possibly lower costs than an abortion. Disadvantages mentioned by participants included side effects and decreased use of contraception.

Commentary

Period pills are medications that are used to induce menses when there is a missed period or late period and a suspicion of possible pregnancy. The process often is called “menstrual regulation.”¹ However, period pills differ from abortion pills because the pregnancy has not yet been diagnosed or confirmed.

Period pills have been used globally for many years, especially in areas where abortion is illegal. Period pills traditionally consisted of taking misoprostol, but mifepristone and misoprostol also can be used. The combination of mifepristone and misoprostol is 98% effective when used as menstrual regulation.² They are safe to take when there is no pregnancy. Misoprostol is used to treat gastric ulcers in nonpregnant people, and it has been shown that mifepristone does not cause adverse effects when taken by healthy nonpregnant people.

Menstrual regulation offers the ability to prevent a pregnancy, without confirming that a pregnancy has been established. This may be more acceptable to some patients who do not want to know if they are pregnant before taking these medications. However, because the pills may not work 100% of the time, those taking the pills should be sure they will have an abortion if the pills do not work. Misoprostol is known to cause birth defects. In addition, patients should have regular periods to know when their period is late.

This survey demonstrates that a substantial proportion of U.S. females are interested in using period pills and even more would like them to be available for others. It makes sense that those who are younger, have had a previous abortion, and have experienced obstacles in accessing reproductive healthcare in the past would be more supportive of period pills. Patients may prefer the ambiguity surrounding a possible pregnancy and may not want to know if they indeed are pregnant before taking these medications.

Patients already can access period pills from online websites such as www.periodpills.org. It is unknown how many people in the United States actually are using them at this time. Nevertheless, it is important that providers understand the concept behind menstrual regulation and how patients may be using these medications.

Rebecca H. Allen, MD, MPH, is Professor, Department of Obstetrics and Gynecology, Warren Alpert Medical School of Brown University, Women & Infants Hospital, Providence, RI.

References

1. Alam A, Bracken H, Bart Johnston H, et al. Acceptability and feasibility of mifepristone-misoprostol for menstrual regulation in Bangladesh. Int Perspect Sex Reprod Health. 2013;39(2):79-87.

2. Cui-Lan L, Chen DJ, Deng YF, et al. Feasibility and effectiveness of unintended pregnancy prevention with low-dose mifepristone combined with misoprostol before expected menstruation. Hum Reprod. 2015;30(12):2794-2801.