The 91 year old was taken to Aberdeen Royal Infirmary in Scotland on Wednesday. Although his exact length of stay is uncertain, the palace said he will likely remain hospitalized for a few more days.
This makes for the prince's third hospitalization in the last eight months. He was hospitalized for five days in June with a bladder infection that may have been aggravated by his appearance at a flotilla as part of Queen Elizabeth's Jubilee celebration. In December, he underwent a successful coronary stent procedure to clear a blocked artery.
The Associated Press contributed to this report.