Methodist Hospital spokesman George Kovacik said in an emailed statement that doctors are still optimistic the 88-year-old Bush will make a full recovery, but are being "extra cautious" with his care. Bush is in stable condition, he said.
Bush was hospitalized Nov. 23 for treatment of a bronchitis-related cough. Hospital officials have said Bush has been receiving physical therapy to increase his strength.
Bush spokesman Jim McGrath said on Thursday Bush could be released in time for Christmas.
However, Kovacik said Sunday a discharge date has not been set, and it remains unclear whether the 41st president will be able to spend the holiday at home. Kovacik said that could be decided Monday, Christmas Eve.