COMPARISON OF MEDICATION ABORTION REGIMENS
MIFEPRISTONE WITH MISOPROSTOL REGIMENS
- Mifepristone, in a regimen with misoprostol, was approved by the FDA for abortion in 2000. The label was updated in 2016 to reflect best evidence at the time and facilitate improved efficacy, safety, convenience, and side effects (FDA label 2016).
- Mifepristone 200 mg and misoprostol 800 mcg has an efficiency of 95-99% prior to 63 days gestational age. Data has demonstrated high rates of success of mifepristone 200 mg and misoprostol 800 mcg followed by a 2nd dose of misoprostol 4 hours later, at 63-77 days gestational age (NAF 2022, Dzuba 2020)
- In light of COVID-19, many organizations implemented telemedicine MAB which has been demonstrated to be safe and effective (Aiken 2021, Upadhyay 2022). Sample protocols can be adapted for practice setting in office or via telemedicine.
Evidence-Based Mifepristone Regimens
Based on evidence up to 2022, Partially adapted from NAF Clinical Practice Guidelines 2022
|Gestational Age||Mifepristone Dose (Day 1)||Misoprostol Dose & Route||Efficacy||Core References|
Mifepristone 200mg PO
|Misoprostol 800 mcg buccal, vaginal1, 2 or sublingual3 24-48 hours after mifepristone||95-99%|
|64 – 70 days||Consider 2nd misoprostol 800mcg 4 hours after 1st dose for patients at 63 days or over
|71 – 77 days4||Recommend 2nd misoprostol 800mcg 4 hours after 1st dose for patients >70 days
|Dzuba 2020, Larsson 2019, Kapp 2019|
- Vaginal route enables wider time frame for use of misoprostol, 0-72 hours after mifepristone, with highest efficacy rates between 24-48 hours.
- Primary studies demonstrating efficacy from 64-70 days used buccal and sublingual misoprostol regimens; updated evidence confirms similar efficacy with vaginal route in this gestational age range (Hsia 2019).
- Sublingual misoprostol dose range 400-800mcg. Fewer side effects shown with lower dose though may have lower efficacy rates (Von Hertzen 2010).
- MAB at 71-77 days LMP is evidence-based, and success rates in the late first trimester are higher with repeat misoprostol doses (Kapp 2019, Dzuba 2020, 2020).
- Protocols > 77 days, used in some global settings, tend to require multiple doses of misoprostol (Hamoda 2003,2005; Lokeland 2010, Kapp 2019, Ipas 2021, WHO 2022).
- Misoprostol-only is another safe regimen (Moseson 2021, Stillman 2020), though may take more time but can be nearly as effective as regimens with mifepristone (Moseson 2021, Blum 2012, Kulier 2011). Recommended regimen: misoprostol 800 mcg buccally, vaginally, or sublingually; repeat every 3 hours as needed until expulsion of pregnancy. (Ipas 2021, Sheldon 2019, Raymond 2019).
- Misoprostol is available over the counter in many countries, and by prescription in the U.S. and is approved to treat arthritis and ulcers. Misoprostol alone may be easier for many to obtain, more widely available, and less expensive than the combination with mifepristone. The misoprostol-only protocol can be useful for those who choose SMMA. People choosing to self-manage their abortion may source it through online pharmacies, veterinarian supply shops, or other means.More information about self-managed abortion safety and access is available at the following sites: World Health Organization, Aid Access, Women on Web.
|Gestational Age||Misoprostol Dose & Route||Efficacy||Core References|
|< 63 days||Misoprostol 800 mcg vaginal, sublingual, or buccal every 3 hours x 3 doses until expulsion||84-96%||Moreno-Ruiz 2007, Von Hertzen 2007
Gynuity 2013, Ipas 2021, WHO 2022
|64 – 70 days||As above.
Additional doses may be used until expulsion of pregnancy.
93% with 4th dose
|Sheldon 2019, Ipas 2021, WHO 2022|
|Up to 91 days||75-81%||Raymond 2019, Kapp 2019,
Ipas 2021, WHO 2022
- Increased efficacy & side effects w/ SL vs. buccal miso in misoprostol-only to 70 days GA (Sheldon 2019).
Methotrexate (50 mg/m2) injection when combined with misoprostol can be used for termination of pregnancy or with pregnancy of unknown location (PUL). It is also an effective treatment for early unruptured ectopic pregnancy with eligibility that includes hCG <5000. Success is determined by serial hCG testing and clinical improvement (Barnhart 2021, Seeber 2006).
A new MAB protocol for <12 weeks includes using letrozole 10 mg orally daily for three days followed by misoprostol 800mcg sublingually on day 4. More research is needed on this regimen (WHO 2022).