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Study: Evidence-Based Medical Abortion Regimen 'Highly Effective,' Safe

Study: Evidence-Based Medical Abortion Regimen 'Highly Effective,' Safe

February 26, 2015 —Summary of "Efficacy and Safety of Medical Abortion Using Mifepristone and Buccal Misoprostol Through 63 Days," Gatter et al., Contraception, Jan. 14, 2015.

"Despite the growing literature supporting evidence-based provision of medical abortion, some providers are required by law to limit the provision of medical abortion to that regimen which was FDA-approved more than a decade ago," according to a study by Mary Gatter of Planned Parenthood Los Angeles and colleagues.

Gatter and colleagues sought "to assess, in a much larger cohort of patients [than a previous 2008 prospective study], the safety and efficacy of an evidence-based medical abortion regimen utilizing 200 milligrams mifepristone orally followed by home use of 800 micrograms misoprostol buccally 24-48 hours later through 63 days estimated gestational age."


The researchers analyzed data from PPLA's network of urban health care clinics in Los Angeles on women presenting for medical abortion between April 1, 2006, and May 31, 2011.

The PPLA facilities since April 2006 have used an evidence-based regimen for medical abortions that "consists of mifepristone 200 mg orally at the health center followed by misoprsotol 800 mcg buccally used by the patient at home 24 to 48 hours later." In February 2009, "the upper gestational age limit for this regimen" increased from 56 days to 63 days. In addition, patients as of 2007 "also received routine antibiotic coverage beginning on the day of the mifepristone administration."

Throughout the study, "[a]ll patients were scheduled to return in 7 to 14 days for a post abortion evaluation" and the study's medical protocols "allowed for repeat doses of misoprostol for patients who had an incomplete medical abortion," according to the researchers.

The researchers defined a "successful abortion" for the purposes of the study "as expulsion of the pregnancy without the need for aspiration." They wrote that "[p]atients who required aspiration for an ongoing pregnancy or symptoms such as pain or bleeding were considered to have had unsuccessful medical abortions."


Overall, the study results included 13,373 women who completed an evidence-based medical abortion regimen and returned for a follow-up visit during the study period. According to the study, the most frequent gestational age range that was between 43 and 49 days (36%), while the least common was 22 to 28 days (4.1%).

The researchers found that 97.7% of women who received medical abortion using the evidence-based regimen had a successful abortion.

Only 307 (2.3%) of the women underwent aspiration, including 70 (0.5%) women who had a continuing pregnancy and 237 (1.8%) women who needed aspiration for a reason other than ongoing pregnancy, most often because of reported bleeding and/or pain symptoms. According to the study, the odds of ongoing pregnancy were 0.15% for a gestational age range of 36 to 42 days and 1.63% for a gestational age range of 57 to 63 days. The researchers noted that when "[c]ompared with the reference category (43 to 49 days), odds of ongoing pregnancy were greater for those at the highest gestational age."

Among all the women in the study, six needed to be hospitalized for any reason, including two as the result of an infection and four for transfusion. Incidence of the need for hospitalization was at or below 0.1% among all ranges of gestational ages.

In addition, the study found that among the 7,335 women for whom data on the need for a repeat dose of misoprostol were available, 87 (1.2%) of the women received a repeat dose.


"This study demonstrates that the evidence-based regimen for medical abortion ... is highly effective" and "safe ... through 63 days estimated gestational age," the researchers wrote.

They noted that the study's 97.7% overall success rate "is higher than the efficacy rates reported in two pivotal trials used in submission for FDA approval of mifepristone, yet utilizes one-third the dose of mifepristone ... and buccal administration and home use of misoprostol rather than oral administration in the clinic."

They added that even though "efficacy is lower at later gestational ages, even in the 57 to 63 day range, this evidence-based regimen was still more effective than rates reported in the FDA-approved regimen, which sets the upper gestational age limit at 49 days."

Further, the researchers wrote that "the rates of unsuccessful abortion in this study are lower than the rates reported in the two trials that were initially submitted to the FDA for approval of mifepristone."

According to the researchers, the study "adds to the growing literature supporting provision of medical abortion using evidence-based regimens, and supports the conclusion that legislative efforts to restrict medical abortion to the FDA regimen are based on political goals to restrict abortion services, not efficacy or patient safety."