How late in pregnancy can a medical abortion be performed?

Medical Abortion Gestational Age Limits

Medical abortion can be safely performed up to 70 days (10 weeks) of gestation using the standard FDA-approved regimen of mifepristone and misoprostol, with different protocols available for later gestations up to 27 6/7 weeks. 1, 2

First Trimester Medical Abortion (Up to 10 Weeks)

• The FDA-approved medication abortion regimen includes mifepristone followed by misoprostol and is safe and effective through 70 days (10 weeks) of gestation 1, 2
• Evidence-based regimen using 200 mg of mifepristone orally followed by home use of 800 mcg misoprostol buccally 24-48 hours later shows 97.7% efficacy through 63 days (9 weeks) of gestation 3
• Efficacy is highest at 29-42 days (98.8%) and decreases slightly at 57-63 days (95.5%) of gestation 3

Second Trimester Medical Abortion (After 10 Weeks)

• Medical abortion can be performed throughout the second trimester (12-27 6/7 weeks), with earlier gestations (12-20 weeks) having shorter abortion times than later gestational ages 4, 5
• The combination of mifepristone and misoprostol is the most effective and fastest regimen for second-trimester medical abortion, with 95% of abortions complete within 24 hours of misoprostol administration 4
• If mifepristone is unavailable, misoprostol alone can be used with approximately 80-85% abortion completion rates at 24 hours 4
• Medical abortion using mifepristone-misoprostol or misoprostol-only regimens can be performed up to 27 6/7 weeks of gestation 5

Legal and Gestational Age Limits

• In England and Wales, medical and surgical abortions can be performed up to and including 23 weeks and 6 days of gestation according to national statistics 6
• The Society for Maternal-Fetal Medicine (SMFM) supports access to abortion without unnecessary barriers, including via telemedicine abortion care 6

Considerations by Gestational Age

• For medical abortions before 9 weeks (63 days), outpatient management with home expulsion is appropriate 6
• For medical abortions between 14 0/7 and 27 6/7 weeks, care should be individualized with consideration to reducing misoprostol dose in low-resource settings or at 24 0/7 weeks of gestation or later 5
• The risk of complications increases with advancing gestational age, with higher rates of incomplete abortion requiring aspiration at later gestations 3

Safety Considerations

• Rates of serious complications such as infection requiring hospitalization (0.01%) and transfusion (0.03%) are very low with medical abortion through 63 days 3
• Earlier abortion procedures generally result in fewer and less severe adverse events 6
• Misoprostol in the setting of two or more previous cesarean sections is associated with increased risk of uterine rupture compared to one or none, but this risk remains low overall 5

Common Pitfalls to Avoid

• Failing to recognize that different medication regimens are appropriate for different gestational ages 4, 5
• Not considering that earlier abortions (before 9 weeks) can often be managed as outpatient procedures with home expulsion, which may be preferred by patients 6
• Overlooking the need for Rh immune globulin administration for Rh-negative women undergoing abortion at any gestational age 6, 7
• Not recognizing that medical abortion protocols may need adjustment based on gestational age, with higher doses and more frequent administration typically needed at later gestations 4, 5

In summary, medical abortion can be safely performed up to 70 days (10 weeks) using the standard mifepristone-misoprostol regimen, and beyond that up to 27 6/7 weeks using appropriate medication protocols adjusted for gestational age.