Original Research Article| Volume 101, ISSUE 5, P302-308, May 2020

A non-inferiority study of outpatient mifepristone-misoprostol medical abortion at 64–70 days and 71–77 days of gestation



      This open-label non-inferiority study assessed efficacy of a common outpatient medical abortion regimen among people with pregnancies 64–70 days and 71–77 days of gestation.

      Study design

      We defined non-inferiority by a 6% margin of method success. People with intrauterine pregnancies 64–77 days’ gestational age by abdominal ultrasound seeking medical abortion at one of eight clinics and met eligibility criteria were offered participation. Consenting participants took mifepristone 200 mg followed 24–48 h later by misoprostol 800 mcg buccally, and returned after one week for provider evaluation and abdominal ultrasound to determine abortion status. Participants recorded medication use, pregnancy expulsion, daily bleeding and pain scores until the one-week follow up. Clinic staff interviewed participants prior to study discharge to assess acceptability.


      Seven hundred and nineteen participants were enrolled, 393 and 326 in the respective groups. Successful expulsion without surgical intervention was achieved in 92.3% of the earlier gestational age group and 86.7% of the later group (difference in proportions 5.6%, 1-sided 95% CI 9.6). Ongoing pregnancy accounted for 3.6% and 8.7% (p = 0.007) of outcomes, respectively. Participants in the 71–77 day group reported nausea and weakness more frequently. Pain, bleeding and acceptability measures between groups were similar.


      Although the success rate at 71–77 days of gestation was within the non-inferiority margin, we cannot rule out that it is statistically worse than in the previous gestational week. Significantly more ongoing pregnancies in the later group raise concerns about using the regimen at 71–77 days.


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        • Jones R.K.
        • Witwer E.
        • Jerman J.
        Abortion incidence and service availability in the United States, 2017.
        Guttmacher Institute, New York2019 ( Accessed September 18, 2019)
        • Abbas D.
        • Chong E.
        • Raymond E.G.
        Outpatient medical abortion is safe and effective through 70 days gestation.
        Contraception. 2015; 92: 197-199
        • Chen M.J.
        • Creinin M.D.
        Mifepristone with buccal misoprostol for medical abortion: a systematic review.
        Obstet Gynecol. 2015; 126: 12-21
      1. Jones RK, Boonstra HD. The public health implications of the FDA update to the medication abortion label. June 30, 2016. Accessed June 6, 2019.

        • Hsia J.K.
        • Lohr P.A.
        • Taylor J.
        • Creinin M.D.
        Medical abortion with mifepristone and vaginal misoprostol between 64 and 70 days' gestation.
        Contraception. 2019; 100: 178-181
        • Schaff E.A.
        • Fielding S.L.
        • Westhoff C.
        Randomized trial of oral versus vaginal misoprostol 2 days after mifepristone 200 mg for abortion up to 63 days of pregnancy.
        Contraception. 2002; 66: 247-250
        • Sanhueza Smith P.
        • Peña M.
        • Dzuba I.G.
        • et al.
        Safety, efficacy and acceptability of outpatient mifepristone-misoprostol medical abortion through 70 days since last menstrual period in public sector facilities in Mexico City.
        Reprod Health Matters. 2015; 22: 75-82
        • Boersma A.A.
        • Meyboom-de Jong B.
        • Kleiverda G.
        Mifepristone followed by home administration of buccal misoprostol for medical abortion up to 70 days of amenorrhoea in a general practice in Curaçao.
        Eur J Contracept Reprod Health Care. 2011; 16: 61-66
        • Gatter M.
        • Cleland K.
        • Nucatola D.L.
        Efficacy and safety of medical abortion using mifepristone and buccal misoprostol through 63 days.
        Contraception. 2015; 91: 269-273
        • Cleland K.
        • Crenin M.D.
        • Nucatola D.
        • Nshom M.
        • Trussel J.
        Significant adverse events and outcomes after medical abortion.
        Obstet Gynecol. 2013; 121: 166-171
        • Winikoff B.
        • Dzuba I.G.
        • Creinin M.D.
        • et al.
        Two distinct oral routes of misoprostol in mifepristone medical abortion.
        Obstet Gynecol. 2008; 112: 1303-1310
        • Ashok P.W.
        • Kidd A.
        • Flett G.M.
        • Fitzmaurice A.
        • Graham W.
        • Templeton A.
        A randomized comparison of medical abortion and surgical vacuum aspiration at 10–13 weeks gestation.
        Human Reprod. 2002; 17: 92-98
        • Gouk E.V.
        • Lincoln K.
        • Khair A.
        • Haslock J.
        • Knight J.
        • Cruickshank D.J.
        Medical termination of pregnancy at 63 to 83 days gestation.
        Br J Obstet Gynaecol. 1999; 106: 535-539
        • Hamoda H.
        • Ashok P.W.
        • Flett G.M.
        • Templeton A.
        Medical abortion at 64 to 91 days of gestation: a review of 483 consecutive cases.
        Am J Obstetrics Gynecol. 2003; 188: 1315-1319
        • Hamoda H.
        • Ashok P.W.
        • Flett G.M.
        • Templeton A.
        Medical abortion at 9–13 weeks' gestation: a review of 1076 consecutive cases.
        Contraception. 2005; 71: 327-332
      2. Medical management of abortion. Geneva: World Health Organization; 2018.

        • Kapp N.
        • Eckersberger E.
        • Lavelanet A.
        • Rodriguez M.I.
        Medical abortion in the late first trimester: a systematic review.
        Contraception. 2019; 99: 77-86
      3. An overview of abortion laws. Guttmacher Institute; Accessed September 20, 2017.

        • Roberts S.C.M.
        • Gould H.
        • Kimport K.
        • Weitz T.A.
        • Foster Greene D.
        Out-of-pocket costs and insurance coverage for abortion in the United States.
        Women's Health Issues. 2014; 24: e211-e218
      4. Medical management of first-trimester abortion: Society of Family Planning clinical guideline. Contraception. 2014;89:148-61.

        • Winikoff B.
        • Dzuba I.G.
        • Chong E.
        • et al.
        Extending outpatient medical abortion services through 70 days of gestational age.
        Obstet Gynecol. 2012; 120: 1070-1076
        • Blackwelder W.C.
        Proving the null hypothesis in clinical trials.
        Control Clin Trials. 1982; 3: 345-353
      5. Accessed August 12, 2013.

        • Cohen J.
        Statistical power analysis for the behavioral sciences.
        Academic press, New York1977
        • Larsson A.
        • Rönnberg A.M.
        Expanding a woman's options to include home use of misoprostol for medical abortion up until 76 days: an observational study of efficacy and safety.
        Acta Obstet Gynecol Scand. 2019; 98: 747-752
      6. Castillo PW, Sanhueza Smith P, Lugo Hernández EM, Castañeda Vivar JJ, Bousiéguez M, Dzuba IG. Does a repeat dose of 800 mcg misoprostol following mifepristone improve outcomes in the later first trimester? A retrospective chart review in Mexico City. Poster. National Abortion Federation's annual meeting; 2017.

        • Csapo A.I.
        • Pulkkinen M.
        Indispensability of the human corpus luteum in the maintenance of early pregnancy: luteectomy evidence.
        Obstet Gynecol Surv. 1978; 33: 69-81
        • Nakajima S.T.
        • Nason F.G.
        • Badger G.J.
        • Gibson M.
        Progesterone production in early pregnancy.
        Fertil Steril. 1991; 55: 516-521
        • Raymond E.
        • Chong E.
        • Winikoff B.
        • et al.
        TelAbortion: evaluation of a direct to patient telemedicine abortion Service in the United States.
        Contraception. 2019; 100: 173-177