From Science Week:

“There are two highly controversial vows in the original Hippocratic Oath that physicians continue to ponder and struggle with as a profession: the pledges never to participate in euthanasia and abortion…. [T]he relevant sections are simply omitted in most oaths administered by US medical schools. As of 1993, only 14 percent of such oaths prohibited euthanasia, and only 8 percent prohibited abortion.”