Last reviewed: February 7, 2021
Recommended regimen before 13 weeks gestation:
- Misoprostol 800mcg buccally, sublingually or vaginally every three hours until expulsion.
Strength of recommendation: Strong
Quality of evidence:
- Up to nine weeks gestation: Moderate
- 9-13 weeks gestation: Low
Misoprostol-only abortion up to 9 weeks
The only multicenter randomized controlled trial to compare different misoprostol-only dosing intervals showed that complete abortion rates are equivalent when misoprostol is given vaginally every 3-12 hours or sublingually every three hours for three doses. Sublingual dosing had a higher incidence of side effects than vaginal dosing (von Hertzen et al., 2007). A 2018 systematic review summarizing data on effectiveness of misoprostol alone for medical abortion found that vaginal, buccal and sublingual administration result in similar rates of surgical intervention, while oral administration resulted in significantly more (Raymond, Harrison, & Weaver, 2019). A trial that randomized women with pregnancies up to 10 weeks to either buccal or sublingual misoprostol (800mcg every three hours for three doses) found that sublingual administration led to significantly fewer continuing pregnancies at follow-up, 1.1% compared with 5.5% (Sheldon et al., 2019). Women in the sublingual group experienced more fever and chills than women in the buccal administration group.
Misoprostol-only abortion between 9-13 weeks
There is scant evidence upon which to recommend an appropriate misoprostol-only regimen between 9-13 weeks. Findings from comparative trials indicate that vaginal and sublingual dosing have similar efficacy and are superior to oral dosing (Ganguly et al., 2010; Van Bogaert & Misra, 2010). Several small cohort studies confirm the effectiveness of the both the vaginal and sublingual routes, and also confirm increased success when multiple doses of misoprostol are used (Carbonell Esteve et al., 1998; Carbonell et al., 1999; Carbonell et al., 2001; Grapsas et al., 2008; Kapp, Eckersberger, Lavelanet, & Rodriquez, 2018; Tang, Miao, Lee, & Ho, 2002). There is strong evidence in randomized controlled trials of misoprostol-only regimens that support using a vaginal dosing interval of every three hours for gestations over 13 weeks (von Hertzen et al., 2009). Extrapolating from the evidence supporting repeat doses of sublingual or vaginal misoprostol at gestations both below nine and above 13 weeks, the evidence-based regimen recommended for gestations below nine weeks may be used for gestations between 9-13 weeks.
Safety and effectiveness of misoprostol-only abortion has been demonstrated in adolescents with pregnancies up to nine weeks gestation (Velazco et al., 2000) and between 9-12 weeks gestation (Carbonell et al., 2001). Success rates of misoprostol-only abortion in young women are similar to those seen in studies of older women.
Carbonell Esteve, J. L., Varela, L., Velazco, A., Cabezas, E., Tanda, R., & Sanchez, C. (1998). Vaginal misoprostol for late first trimester abortion. Contraception, 57(5), 329-333.
Carbonell, J. L., Varela, L., Velazco, A., Tanda, R., & Sanchez, C. (1999). Vaginal misoprostol for abortion at 10-13 weeks’ gestation. The European Journal of Contraception and Reproductive Health Care, 4(1), 35-40.
Carbonell, J. L., Velazco, A., Varela, L., Tanda, R., Sanchez, C., Barambio, S., & Mari, J. (2001). Misoprostol for abortion at 9-12 weeks’ gestation in adolescents. The European Journal of Contraception and Reproductive Health Care, 6(1), 39-45.
Ganguly, R. P., Saha, S. P., Mukhopadhyay, S., Bhattacharjee, N., Bhattacharyya, S. K., & Patra, K. K. (2010). A comparative study on sublingual versus oral and vaginal administration of misoprostol for later first and early second trimester abortion. Journal of the Indian Medical Association, 108(5), 283-286.
Grapsas, X., Liberis, V., Vassaras, G., Tsikouras, P., Vlachos, G., & Galazios, G. (2008). Misoprostol and first trimester pregnancy termination. Clinical and Experimental Obstetrics and Gynecology, 35(1), 32-34.
Kapp, N., Eckersberger, E., Lavelanet, A., & Rodriguez, M. I. (2018). Medical abortion in the late first trimester: a systematic review. Contraception, ePub ahead of print.
Raymond, E., Harrison, M, & Weaver, M. (2019). Efficacy of misoprostol alone for first-trimester medical abortion: A systematic review. Obstetrics & Gynecology, 133, 137-147.
Sheldon, W. R., Durocher, J., Dzuba, I. G. , Sayette, H., Martin, R., Velasco, M. C., & Winikoff, B. (2019). Early abortion with buccal versus sublingual misoprostol alone: A multicenter, randomized trial. Contraception, 99(5), 272-277.
Tang O. S., Miao, B. Y., Lee, S. W. H., & Ho, P. C. (2002). Pilot study on the use of repeated doses of sublingual misoprostol in termination of pregnancy up to 12 weeks gestation: Efficacy and acceptability. Human Reproduction, 17(3), 654-658.
Velazco A., Varela, L., Tanda, R., Sanchez, C., Barambio, S., Chami, S., … Carbonell, J. L. (2000). Misoprostol for abortion up to 9 weeks’ gestation in adolescents. European Journal of Contraception and Reproductive Health Care, 5(4), 227-233.
Van Bogaert, L. J., & Misra, A. (2010). Anthropometric characteristics and success rates of oral or vaginal misoprostol for pregnancy termination in the first and second trimesters. International Journal of Gynecology & Obstetrics, 109(3), 213-215.
von Hertzen, H., Piaggio, G., Huong, N. T., Arustamyan, K., Cabezas, E., Gomez, M., & Peregoudov, A. (2007). Efficacy of two intervals and two routes of administration of misoprostol for termination of early pregnancy: A randomised controlled equivalence trial. The Lancet, 369(9577), 1938-1946.
von Hertzen, H., Piaggio, G., Wojdyla, D., Nguyen, T. M., Marions, L., Okoev, G., & Peregoudov, A. (2009). Comparison of vaginal and sublingual misoprostol for second trimester abortion: Randomized controlled equivalence trial. Human Reproduction, 24(1), 106-112.
World Health Organization. (2018). Management of Medical Abortion. Geneva: World Health Organization.