Last time I checked, even the most extreme libertarians considered protecting innocents from murder to be a legitimate exercise of state power.
States have murder laws that can apply to abortion. They could be enforced.
If you are aware of such a murder, demand that your state prosecutor indict, then hold murder trials of women who have had abortions.
I doubt the feds could find a way to stop a State from holding trials. - And I also doubt that they could ever actually jail any women.
Um, the Supreme Court would throw out any such verdict because it would violate the "right to privacy" in Roe. States have to obey the Supreme Court.
First, outlaw the practice. Then, prosecute the criminals. However, it's best to strike at the weakest link first, and that's the abortionist.