Last reviewed: September 29, 2022
Recommendation:
- Less than 22-24 weeks gestation with one uterine scar: No changes to recommended regimens necessary.
- More than 22-24 weeks gestation with one uterine scar or 13-24 weeks gestation with more than one uterine scar: Consider decreasing the misoprostol dose with or without lengthening the misoprostol dosing interval. There is insufficient evidence to know if this impacts the risk of uterine rupture.
Strength of recommendation: Weak
Quality of evidence: Very low
Risk of uterine rupture with medical abortion
Uterine rupture has been reported during medical abortion at or after 13 weeks gestation in people with and without a uterine scar. The risk of uterine rupture for anyone undergoing a medical abortion at or after 13 weeks gestation is very rare, occurring in fewer than 1 in 1,000 people (Goyal, 2009). In a meta-analysis of 16 studies of 3,556 women undergoing medical abortion at or after 13 weeks gestation with combined or misoprostol-only regimens, three women suffered uterine rupture resulting in a rate of 0.28% with a previous cesarean section and 0.04% without (Goyal, 2009).
One single-center retrospective review of 279 women undergoing abortion between 14-26 weeks included 60 women with one and 26 women with more than one uterine scar (Küçükgöz Güleç et al., 2013). Women received misoprostol 200mcg vaginally every four hours; three had a uterine rupture. In another retrospective review of 263 women between 12-24 weeks undergoing misoprostol-only abortion, 48 had one and 29 had more than one scar; one rupture was observed in a woman with three prior cesarean sections who received a misoprostol regimen of 200mcg sublingually every three hours (Cetin et al., 2016). A third retrospective review included 231 women with one and 37 women with two prior cesarean deliveries, and used a regimen of 800mcg of misoprostol as a loading dose followed by 200mcg every two hours for three doses; no women experienced rupture (Torriente, Steinberg, & Joubert, 2017).
One single-center prospective study of 250 women undergoing uterine evacuation for fetal demise using a low-dose misoprostol regimen included 95 participants with a uterine scar (Shakir, 2022). Those with gestations between 13-17 weeks received 100mcg of misoprostol vaginally every six hours for 24 hours, and between 18-24 weeks received 50mcg of misoprostol. No ruptures occurred, however only 67% had completely aborted after 24 hours.
Regimen for people with a uterine scar
Due to the rarity of uterine rupture in people with a previous scar, no clear guidance can be obtained from the published literature (Borgatta & Kapp, 2011; Daponte, Nzewenga, Dimopoulos, & Guidozzi, 2006; Daskalakis et al., 2004; Dickinson, 2005; Morris et al., 2017).
Expert opinion supports:
- No change in medical abortion regimen for people with one uterine scar whose gestation is less than 22-24 weeks.
- After 22-24 weeks gestation with a single uterine scar or 13-24 weeks gestation with more than one uterine scar:
- Consider decreasing the dose of misoprostol with or without lengthening the dosing interval (Ho et al., 2007; Küçükgöz Güleç et al., 2013).
There is insufficient evidence to know if changing the dosing regimen will decrease the risk of uterine rupture.
References
Borgatta, L., & Kapp, N. (2011). Society of Family Planning Clinical Guideline 20111: Labor induction abortion in the second trimester. Contraception, 84(1), 4-18.
Cetin, C., Buyukkurt, S., Seydaoglu, G., Kahveci, B., Soysal, C., & Ozgunen, F. T. (2016). Comparison of two misoprostol regimens for mid-trimester pregnancy terminations after FIGO’s misoprostol dosage recommendation in 2012. The Journal of Maternal-Fetal & Neonatal Medicine, 29(8), 1314-1317.
Daponte, A., Nzewenga, G., Dimopoulos, K. D., & Guidozzi, F. (2006). The use of vaginal misoprostol for second-trimester pregnancy termination in women with previous single cesarean section. Contraception, 74(4), 324-327.
Daskalakis, G. J., Mesogitis, S. A., Papantoniou, N. E., Moulopoulos, G. G., Papapanagiotou, A. A., & Antsaklis, A. J. (2004). Misoprostol for second trimester pregnancy termination in women with prior caesarean section. BJOG: An International Journal of Obstetrics & Gynaecology, 112(1), 97-99.
Dickinson, J. E. (2005). Misoprostol for second-trimester pregnancy termination in women with a prior cesarean delivery. Obstetrics & Gynecology, 105(2), 352-356.
Goyal, V. (2009). Uterine rupture in second-trimester misoprostol-induced abortion after cesarean delivery: A systematic review. Obstetrics & Gynecology, 113(5), 1117-1123.
Ho, P. C., Blumenthal, P. D., Gemzell-Danielsson, K., Gómez Ponce de León, R., Mittal, S., & Tang, O. S. (2007). Misoprostol for the termination of pregnancy with a live fetus at 13 to 26 weeks. International Journal of Gynecology & Obstetrics, 99(2), 178-181.
Küçükgöz Güleç, Ü., Urunsak, I. F., Eser, E., Guzel, A. B., Ozgunen, F. T., Evruke, I. C., & Buyukkurt, S. (2013). Misoprostol for midtrimester termination of pregnancy in women with 1 or more prior cesarean deliveries. International Journal of Gynecology & Obstetrics, 120, 85-87.
Morris, J. L., Winikoff, B., Dabash, R., Weeks, A., Faundes, A., Gemzell-Danielsson, K., … Visser, G. H. A. (2017). FIGO’s updated recommendations for misoprostol used alone in gynecology and obstetrics. International Journal of Gynecology & Obstetrics, 138(3), 363-366.
Shakir, H.M. (2022). Safety of vaginal misoprostol for the termination of second trimester miscarriage in women with previous uterine scar in Iraq. Archives of Razi Institute, 77(1), 199-204.
Torriente, M. C., Steinberg, W. J., & Joubert, G. (2017). Misoprostol use for second-trimester termination of pregnancy among women with one or more previous cesarean deliveries. International Journal of Gynecology & Obstetrics, 138, 23-27.