Once researchers saw the potential of methotrexate as a medical abortion drug, they tried it in combination with misoprostol, usually given as a vaginal suppository. Because it can also cause uterine contractions, it has become a second component of medical abortion along with either methotrexate or mifepristone. The use of misoprostol by itself for medical abortion has been studied, particularly in Brazil, where abortion is illegal and misoprostol is the easiest of the three medical abortion drugs to acquire. These studies have found that although misoprostol is about as effective as both two-drug combinations, there are many more unpleasant side effects. Among the side effects of misoprostol are diarrhea, nausea and vomiting.
Some women also get hot flashes or episodes of fever.
Possibly because it enters the bloodstream more gradually, misoprostol seems to have fewer side effects when given as a suppository than by mouth. Based on what we know today, of the three drugs we have mentioned, misoprostol is the most likely to cause birth defects. Limb and cranial abnormalities have been reported in babies born to women who remained pregnant after using misoprostol. Obviously, the newer the drug the less information is available. For instance, there is little or no evidence that mifepristone can cause any particular problem.