Human Reproduction, Vol. 15, No. 12, 2686-2688,
December 2000
© 2000 European Society of Human Reproduction and Embryology
Letters to the Editor |
Use of vaginal misoprostol for abortion
Department of Obstetrics and Gynecology, USC Keck School of Medicine, University of Southern California, 1240 No. Mission Rd. L1009, Los Angeles, CA 90033, USA
Dear Sir,
We believe that several of the conclusions of the authors of `Vaginal misoprostol alone for medical abortion up to 9 weeks of gestation: efficacy and acceptability' (Ngai et al., 2000
) are unsubstantiated. We agree that a prospective, randomized controlled trial is necessary to evaluate whether moistening of vaginally administered misoprostol tablets improves the efficacy of this agent for abortion. However, we believe that the authors conclusions: (i) that there is no difference in efficacy between the group who had moistened misoprostol and the group who had dry misoprostol; (ii) that the failure rate of this method was too high for clinical acceptability; and (iii) that misoprostol alone has low acceptability, were incorrect or misleading.
Although the sample size of the study was calculated to provide appropriate statistical significance and power, the estimated effectiveness on which the sample size was based was erroneous. Recent studies using moistened misoprostol for abortion of gestations of <9 weeks duration have reported the effectiveness to be 88–94% (Carbonell et al., 1997a,b; Jain et al ., 1999). Use of unmoistened misoprostol in previous studies resulted in a 66% effectiveness (Bugalho et al., 1996). A greater number of subjects would be needed to determine whether the difference between an 88 and a 66% efficacy was statistically significant. In this study for gestations of <49 days (n = 37), the efficacy of moistened misoprostol was 94%, compared with 68% for unmoistened misoprostol. A larger sample size would most likely have shown this difference to be statistically significant. The data for gestational ages 50–63 days (n = 43) also shows an increased efficacy with moistened compared with unmoistened misoprostol (77 versus 62%), and also suffers from insufficient sample size to determine statistical significance.
The authors state that the overall efficacy rate of 85% is not `clinically acceptable' but in the largest US trial of mifepristone and misoprostol, the overall efficacy rate for gestations of 
9 weeks was 81.1% (Spitz et al., 1998). Furthermore, this efficacy rate may be clinically acceptable in areas of the world where mifepristone or surgical abortion is not available. The authors also stated that repeated dosing of misoprostol is cumbersome. However: (i) most women abort shortly after receiving one dose of misoprostol and repeated dosing is unnecessary; (ii) the mifepristone + misoprostol treatment protocol requires at least two medication administrations (one for each) and abortion is delayed until after misoprostol is given (Spitz et al., 1998); and (iii) the methotrexate + misoprostol treatment also requires at least two different medication administrations (one for each) and abortion is delayed for as long as 3 weeks (Creinen et al., 1996).
Finally, the authors comment on the acceptability data that they collected, stating that 40% of subjects would not choose this method again. However, they do not report the acceptability results by method group (moistened or dry misoprostol), gestational age, or whether the treatment resulted in success or failure.
We believe that prior data support the conclusion that moistened vaginal misoprostol is a safe, effective and acceptable method of inducing abortion for gestations of 7 weeks with a reported effectiveness of 88–94% (Carbonell et al., 1997a,b, Jain et al ., 1999). This evidence is strengthened by the results of this study in which the abortion rate in pregnancies of <7 weeks gestation was 94% with use of moistened misoprostol.
Notes
1 To whom correspondence should be addressed 
References
Bugalho, A., Faundes, A., Jamisse, L. et al. (1996) Evaluation of the effectiveness of vaginal misoprostol to induce first trimester abortion. Contraception, 53, 243–246.
Carbonell, J.L.L., Varela, L., Velazco, A,. and Fernandez, C. (1997a) The use of misoprostol for termination of early pregnancy. Contraception, 55, 165–168.[ISI][Medline]
Carbonell, J.L.L., Varela, L., Velazco, A. et al. (1997b) The use of misoprostol for abortion at <9 weeks' gestation. Eur. J. Contracept. Reprod. Health Care, 2, 181–185.[Medline]
Creinen, M.D., Vittinghoff, E., Keder, L. et al. (1996) Methotrexate and misoprostol for early abortion: a multicenter trial. I. Safety and efficacy. Contraception, 53, 321–327.[ISI][Medline]
Jain, J.K., Meckstroth, K.R. and Mishell, J.R. (1999) Early pregnancy termination with intravaginally administered sodium chloride solution-moistened misoprostol tablets: historical comparison with mifepristone and oral misoprostol. Am. J. Obstet. Gynecol., 181, 1386–1391.[ISI][Medline]
Ngai, S.W., Tang, O.S., Chan, Y.M. and Ho, P.C. (2000) Vaginal misoprostol alone for medical abortion up to 9 weeks of gestation: efficacy and acceptability. Hum. Reprod., 15, 1159–1162.
Spitz, I.M., Bardin, C.W., Benton, L. and Robbins, A. (1998) Early pregnancy termination with mifepristone and misoprostol in the United States. N. Engl J. Med., 338, 1241–1247.
Department of Obstetrics & Gynaecology, Queen Mary Hospital, Hong Kong
Dear Sir,
Thank you for the opportunity to reply to the comments made by Dr Harwood and Professor Mishell. The calculation of sample size was based on results of previous studies. The complete abortion was only 61% (Koopersmith et al., 1996) with misoprostol alone, while the complete abortion rate was 92% when misoprostol was added (Carbonell et al., 1997). We did explain in our discussion that the difference did not reach statistical significance because the difference was less than that estimated from previous results.
We agree and did state in the discussion of our paper that the complete abortion rate with moistened misoprostol appeared reasonable (94%) in pregnancies with a menstrual delay of 7 weeks. We also pointed out that this deserved further evaluation. However, the complete abortion rate for pregnancies at 7–9 weeks was only 77%, even when water was added. This is much lower than the complete abortion rates of the other methods. Although in the largest US trial (Spitz et al., 1998) the efficacy for gestations of 50–63 days was 77–83%, results are much better in other series (El-Rafaey and Templeton, 1994; Baird et al., 1995; Ashok et al., 1998). The lower efficacy in the US trial may be due to administration of misoprostol by the oral route, or it may be due to lack of experience with medical abortion in the USA, as well as to the design of the study (Spitz et al., 1998). In the large series in Aberdeen, the complete abortion rate with mifepristone and vaginal misoprostol was 96.7% with gestations of >49 days (Ashok et al., 1998).
Of our patients, 40% would not choose the same method again. Among these women, 60% were from the water-added group while the remainder were from the no water-added group; 80% of them were at 7 weeks of gestation. Overall, 60% of them required surgical treatment. The acceptability was much lower than that of the combined mifepristone and prostaglandin regimen (Tang et al., 1993). The reasons for not choosing the method again have already been stated in the article.
We agree that there is a need for developing a regimen using misoprostol alone for medical abortion. However, the regimen described in our paper was not ideal because of the high failure rate and low acceptability by our patients. We are currently working on other protocols using misoprostol alone for medical abortion.
Notes
1 To whom correspondence should be addressed
References
Ashok, P.W., Penney, G.C., Flett, G.M.M. and Templeton, A. (1998) An effective regimen for early medical abortion: a report of 2000 consecutive cases. Hum. Reprod., 10, 2962–2965.
Baird, D.T., Sukcharoen, N. and Thong, K.J. (1995) Randomized trial of misoprostol and cervagem in combination with a reduced dose of misfepristone for induction of abortion. Hum. Reprod., 10, 1521–1527.
Carbonell, J.L.L., Varela, L., Velazce, T. and Fernendez, T. (1997) The use of misoprostol for termination of early pregnancy. Contraception, 55, 165–168.
El-Refaey, H. and Templeton, A.A. (1994) Early induction of abortion by a combination of oral mifepristone and misoprostol administered by the vaginal route. Contraception, 49, 111–114.[ISI][Medline]
Koppersmith, T.B. and Mishel, J.D. (1996) The use of misoprostol for termination of early pregnancy. Contraception, 53, 237–242.
Spitz, I.M., Wayne, B.C., Benton, L. and Robbins, A. (1998) Early pregnancy termination with mifepristone and misoprostol in the United States. N. Engl J. Med., 338, 1241–1247.
Tang, G.W.K., Lau, O.W.K. and Yip, P. (1993) Further acceptability evaluation of RU486 and ONO 802 as abortifacient agent in a Chinese population. Contraception, 48, 267–276.[ISI][Medline]
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