Rep. Gabrielle Giffords is scheduled to undergo surgery Wednesday to place a plastic implant in her skull, the Associated Press reported Tuesday, citing a person familiar with the Arizona Democrat’s care.

Doctors removed part of Giffords’ skull to relieve swelling in her brain after she was shot in January. She had been holding an event for constituents outside a grocery store in Tucson, Ariz., when an attacker opened fire, killing six people and wounding Giffords and a dozen others.

Doctors at TIRR Memorial Hermann in Houston, where Giffords is undergoing rehabilitation, had said they planned to replace the missing portion of her skull with a cranial implant in May.

Giffords was in Florida on Monday to watch the launch of the space shuttle Endeavor. Her husband, Mark Kelly, is commanding the mission.