John Stutsman, an obstetrician-gynecologist and professor of medicine at Indiana University, confirmed to the Indianapolis Star that a transvaginal probe would be required.
Holdman told the Indy Star that such measures are justified to protect "another human life." Indiana's House, Senate and governor's mansion are all controlled by Republicans.
Abortion rights advocates were livid.
"As we've seen in states across the country, this legislation has one clear motive: to make abortion care as inaccessible as possible. This type of legislation is designed to increase barriers to safe, legal abortion by shaming and harassing women," said Tarek Rizk, a spokesman for NARAL. "This burdensome forced-ultrasound mandate is only part of an overall bill that is intended to obstruct women's access to medical-abortion services."