The astronaut suffering from the medical concern, who was not identified, remains in stable condition, the outlet reported.
In a previous statement, NASA revealed it was "monitoring a medical concern with a crew member that arose Wednesday afternoon."
The four-person Crew-11 crew consists of U.S. astronauts Zena Cardman and Mike Fincke, Russian cosmonaut Oleg Platonov and Japanese astronaut Kimiya Yu.
Fincke, the mission's commander, and flight engineer Cardman were anticipated to complete a 6.5 hour spacewalk on Thursday to install hardware outside the ISS.
Astronauts typically live aboard the ISS for stints of six to eight months, and are equipped with basic medical equipment and medications in the event of an emergency. The crew set off for their current eight-month mission from Florida in August and were set to return to Earth in May.
Spacewalks are highly strenuous and involve months of training.
Last year, NASA canceled a planned spacewalk after an astronaut reportedly experienced "spacesuit discomfort." In 2021, U.S. astronaut Mark Vande Hei’s had his spacewalk called off due to a pinched nerve.
NASA did not immediately respond to Fox News Digital’s request for comment.