Doctors say former President George H.W. Bush needs to "build up his energy" before he can be released from a Houston hospital.
Methodist Hospital spokesman George Kovacik said in an email statement Sunday that doctors are still optimistic that the 88-year-old Bush will make a full recovery.
He said doctors are being "extra cautious" with Bush's care.
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.
On Thursday, Bush spokesman Jim McGrath said Bush could be released in time for Christmas. But Kovacik said in Sunday's statement that a discharge date has not been set.