Last reviewed: February 7, 2021
Key Information:
- Dilatation and evacuation (D&E) and medical abortion with mifepristone and misoprostol or misoprostol only are safe and effective methods of abortion.
- Women should be offered a choice of methods when both D&E and medical abortion are available.
- Medical abortion has a higher rate of retained products of conception, failed abortion and minor adverse events.
- D&E requires a trained, experienced provider and specialized equipment.
Quality of evidence: Moderate
Comparison of methods
In the largest randomized trial comparing methods of abortion at or after 13 weeks gestation, 58 women with gestations between 13-20 weeks received D&E and 52 received medical abortion with mifepristone and misoprostol (Kelly, Suddes, Howel, Hewison, & Robson, 2010). Overall rates of complications were the same in the two groups (12%), although the types of complications differed. Five women in the medical arm required uterine evacuation for retained products of conception and one suffered bleeding requiring transfusion; only one woman in the surgical arm required repeat uterine evacuation, one suffered a cervical laceration, and five had hemorrhage that did not require transfusion. A statistically significant proportion of women randomized to medical abortion had more bleeding and pain and found the abortion process less acceptable than women who had D&E. A pilot randomized trial of 18 women with gestations between 14-19 weeks comparing D&E and medical abortion with mifepristone and misoprostol found a higher rate of adverse events, specifically retained placenta and fever, in women undergoing medical abortion, although none were serious (Grimes, Smith, & Witham, 2004).
The largest available retrospective cohort study comes from Nepal and included 2,294 women at or after 13 weeks gestation; 595 underwent D&E and 1,701 had a medical abortion (Kapp, Griffin, Bhattarai, & Dangol, 2020). Complications were rare overall (<1% for D&E, 1.4% for medical abortion), mostly consisting of hemorrhage, amongst both groups. In smaller retrospective cohort studies, women with gestations 13-24 weeks who had medical abortions had an increased rate of failed abortion and retained products of conception with a need for further intervention compared to women who had D&E; The rate of major adverse events including infection, transfusion, hysterectomy and death did not differ between the two methods (Autry, Hayes, Jacobson, & Kirby, 2002; Bryant, Grimes, Garrett, & Stuart, 2011; Sonalkar, Ogden, Tran, & Chen, 2017).
In published studies of medical abortion compared to D&E, rates of intervention for medical abortion may be artificially high because failure has been defined as no expulsion within 24 hours (Bryant et al., 2011) and retained placenta has been diagnosed after two hours (Grimes et al., 2004). In practice, more time may be allowed for successful medical abortion to occur.
Subsequent perinatal outcomes
A Finnish register-based study of first-time mothers compared incidence of adverse birth outcomes among those with no history of previous abortion (364,392 women), those with past history of a medical or surgical abortion at 12 weeks gestation or less (46,589 women), and those with history of a medical or surgical abortion at greater than 12 weeks (7,709 women)(KC, Gissler, & Klemetti, 2020). Investigators found that the risk of any subsequent adverse birth outcome was small, but that risk is higher with increasing gestational age at the time of induced abortion. Women undergoing a later medical abortion had a 1.4 fold increased risk of both preterm birth and low birthweight compared to those having an earlier medical abortion. Women who had a late surgical abortion had a 2.6 fold and 1.5 fold increased risk of extremely preterm birth and very low birthweight compared with women who had an earlier surgical abortion.
The importance of choice
The characteristics of medical abortion and D&E vary widely; in settings where both abortion methods are available and a woman is a candidate for either, she should be offered a choice of abortion method. For women, the choice of abortion procedure is an intensely personal one (Kerns et al., 2018)—some women prefer the speed and predictability of D&E, while others prefer a more “labor-like” process with an intact fetus (Kelly et al., 2010; Kerns et al., 2012). Acceptability and satisfaction with the abortion process is highest when women can choose to receive their preferred method (Kapp & Lohr, 2020). Both randomized trials referenced above (Kelly et al., 2010; Grimes et al., 2004) had difficulty with recruitment due to women’s strong preferences for one method-generally D&E-over the other. In the most recent of these studies, 100% of those randomized to D&E reported they would choose it again compared with only 53% of those randomized to medical abortion (Kelly et al., 2010).To choose the abortion procedure that best facilitates their coping, women need adequate information regarding the two abortion methods and the ability to make their decision autonomously (Kerns et al., 2018).
References
Autry, A. M., Hayes, E. C., Jacobson, G. F., & Kirby, R. S. (2002). A comparison of medical induction and dilation and evacuation for second-trimester abortion. American Journal of Obstetrics & Gynecology, 187(2), 393-397.
Bryant, A. G., Grimes, D. A., Garrett, J. M., & Stuart, G. S. (2011). Second-trimester abortion for fetal anomalies or fetal death: Labor induction compared with dilation and evacuation. Obstetrics & Gynecology, 117(4), 788-792.
Grimes, D. A., Smith, M. S., & Witham, A. D. (2004). Mifepristone and misoprostol versus dilation and evacuation for midtrimester abortion: A pilot randomised controlled trial. BJOG: An International Journal of Obstetrics & Gynaecology, 111(2), 148-153.
Kapp, N., Griffin, R., Bhattarai, N., & Dangol, D.S. (2020). Does prior ultrasonography affect the safety of induced abortion at or after 13 weeks’ gestation? A retrospective study. Acta Obstetricia et Gynecologica Scandinavica, doi: 10.1111/aogs.14040. Epub ahead of print. PMID: 33185906.
Kapp, N. & Lohr, P.A. (2020). Modern methods to induce abortion: Safety, efficacy and choice. Best Practice and Research: Clinical Obstetrics and Gynaecology, 63, 37-44.
KC, S., Gissler, M., & Klemetti, R. (2020). The duration of gestation at previous induced abortion and its impacts on subsequent births: A nationwide registry based study. Acta Obstetricia et Gynecologica Scandinavica, 99(5), 651-659.
Kelly, T., Suddes, J., Howel, D., Hewison, J., & Robson, S. (2010). Comparing medical versus surgical termination of pregnancy at 13-20 weeks of gestation: A randomised controlled trial. BJOG: An International Journal of Obstetrics & Gynaecology, 117(12), 1512-1520.
Kerns, J. L., Light, A., Dalton, V., McNamara, B., Steinauer, J., & Kuppermann, M. (2018). Decision satisfaction among women choosing a method of pregnancy termination in the setting of fetal anomalies and other pregnancy complications: A qualitative study. Patient Education and Counseling, 101(10), 1859-1864.
Kerns, J., Vanjani, R., Freedman, L., Meckstroth, K., Drey, E. A., & Steinauer, J. (2012). Women’s decision making regarding choice of second trimester termination method for pregnancy complications. International Journal of Gynecology & Obstetrics, 116(3), 244-248.
Sonalkar, S., Ogden, S. N., Tran, L. K., & Chen, A. Y. (2017). Comparison of complications associated with induction by misoprostol versus dilation and evacuation for second-trimester abortion. International Journal of Gynecology & Obstetrics, 138, 272-275.
