(covers information from several alternate timelines)
A medical shuttle was a shuttlecraft, equipped with specialized technology and equipment designed to deal with possible medical emergencies, carried aboard Federation starships in the early 23rd century.
In the alternate reality created by Nero's temporal incursion in 2233, Winona Kirk, mother of James Tiberius Kirk, was evacuated from the USS Kelvin in a Kelvin-type medical shuttle when the ship came under attack by the Narada. Winona gave birth to James aboard the shuttle as it was fleeing the area. (Star Trek)