Former first lady Barbara Bush remains in a Houston hospital for treatment of a respiratory-related condition.

The 88-year old wife of former President George H.W. Bush has been at Houston's Methodist Hospital since Monday.

No timetable has been given for her release but Bush family spokesman Jim McGrath has said she is doing well. He says he hospital stay is likely a result of physicians being extra cautious.

Bush and her husband, the 41st president, live in Houston during the winter and in Maine during the warmer months of the year.

[Associated Press]