Many medications, for all the good they do, can also come with some potentially negative side effects. Just think of the laundry list of disclaimers you hear at the end of pharmaceutical commercials. For horses, it’s no different.

Take, for instance, the gastrointestinal cytoprotectant misoprostol: This drug used to prevent or treat right dorsal colitis (an ulcerative inflammatory condition of the colon) in horses has abortigenic properties in humans. So is it safe to administer to pregnant mares? Researchers from the University of Pennsylvania School of Veterinary Medicine’s New Bolton Center have been conducting studies to gather safety data that veterinarians and owners can use to weigh the risks and benefits of misoprostol treatment.

Co-author and reproduction resident Jennifer Linton, VMD, presented their results at the 2014 American Association of Equine Practitioners Convention, held Dec. 6–10 in Salt Lake City, Utah.

In women, misoprostol is used to purposefully terminate pregnancies, Linton explained. In those pregnancies that do continue to term in spite of treatment, the resulting babies sometimes suffer from neurologic, musculoskeletal, and cognitive defects.

Results from a 2013 study (also conducted at the University of Pennsylvania, led by Candace Jacobson, DVM) of 11 pregnant mares administered oral misoprostol mid-gestation resulted in no adverse effects or disrupted pregnancies. To continue this work, Linton wanted to examine the same misoprostol regimen’s safety when administered during early gestation and to evaluate the health of the surviving neonates.

She and her colleagues administered