Low expulsion rates reported for SA+EE contraceptive vaginal rings

Ring expulsions are infrequent overall and are not associated with body mass index (BMI) or parity, according to a recent study in the American Journal of Obstetrics & Gynecology.¹

According to the Centers for Disease Control and Prevention (CDC), “evidence indicates that the combined hormonal patch and the combined vaginal ring provide comparable safety and pharmacokinetic profiles to combined oral contraceptives (COCs) with similar hormone formulations.”² Additionally, the CDC recommends the patch and rings have the same categories as COCs.

In 2018, the FDA approved a ring-shaped contraceptive vaginal system (CVS) for use in a regiment of 21 days in and 7 days out for up to 13 menstrual cycles.¹ The CVS, which releases segesterone acetate (SA) and ethinyl estradiol (EE), has been proven safe and effective and can last a full year without the need for insertion or removal from a provider.

Previous data has focused on the ease of use, effect on sexual function, perceived side effects, and experiences related to ring expulsion for the SA+EE CVS. Investigators conducted a study to further evaluate the impact of ring expulsions on method continuation and pregnancy incidence.

Participants underwent the 21 days in and 7 days out regimen, reporting complete, partial, or no expulsion in a daily paper diary. The CVS coming fully out of the vagina indicated complete expulsion, while the CVS moving out of place but remaining partially within the vagina indicated partial expulsion. Partial expulsions were excluded from the analysis.

There were 2064 participants included in the final analysis, 25% of whom experienced an expulsion during any cycle of the analysis. Most participants with a reported expulsion only had 1 occur, with only 1.5% experiencing 4 or more expulsions in any 1 cycle.

Rings were never out on the day of or following the expulsion in 90% of expulsions. Fifty-seven percent of expulsions occurred during a bowel movement, 37% during exercise, and 4% during sexual intercourse.

Participants with expulsion were more often non-Hispanic, from a US study site, or a college graduate, but expulsions did not differ based on race, age, BMI, or parity. Similar rates of satisfaction were reported among patients with and without expulsions, at 88% and 86%, respectively.

The number of participants experiencing an expulsion decreased with each cycle, at 9% in cycle 1, 4% in cycle 6, and 3% in cycle 13. The rate of multiple expulsions experienced also decreased across cycles, plateauing at approximately cycle 6. The risk of expulsion decreased by half in cycles 2 to 8 vs cycle 1.

Study site, education, and cycle of use remained strong predictors of expulsion in the adjusted regression model. The adjusted odds ratio of expulsion was lower among participants at sites in Latin America vs those in the United States.

Of participants with an expulsion during cycle 1, 5 became pregnant. This indicated a Pearl Index of 3.99 vs 2.99 among participants without expulsion during cycle 1. Additionally, the odds of discontinuation were 31% among participants with an expulsion during cycle 1 vs 26% for participants with no expulsion during cycle 1.

These results indicated low rates of SA+EE CVS expulsion, with expulsion occurrence decreasing over time. Investigators recommended discussing this information when counseling patients to potentially improve overall user satisfaction.

References

1. Plagianos MG, Ramanadhan S, Merkatz RB, et al. Risk factors for and outcomes of ring expulsions with a 1-year contraceptive vaginal system. Am J Obstet Gynecol. 2024;230:548.e1-8. doi:10.1016/j.ajog.2024.01.020
2. Classifications for combined hormonal contraceptives. Centers for Disease Control and Prevention. Accessed May 23, 2024. https://www.cdc.gov/reproductivehealth/contraception/mmwr/mec/appendixd.html