HOUSTON (Reuters) - Former U.S. President George H. W. Bush is being treated at a Houston hospital for complications related to bronchitis and is in stable condition, the hospital said on Thursday.

"President Bush has been in and out of The Methodist Hospital in the Texas Medical Center being treated for complications related to his bronchitis," Bush's office said in a statement released by the hospital. "He is in stable condition, and is expected to be released within the next 72 hours."

Bush was admitted to the hospital last Friday with bronchitis, Bush family spokesman Jim McGrath told Fox News Channel's "Happening Now."

"They were able to successfully treat that piece of it, but he still has a lingering cough and that and the fact that's he's 88 - they're just being extra cautious and holding him until the cough gets better," McGrath said on Thursday.

McGrath said there were fears that Bush would develop pneumonia but that he did not.

"I guess there's always that concern when you're dealing with somebody at that advanced age but thankfully, it didn't turn in that direction," McGrath said. "And the medication and treatment they've used to get a hold of this bronchitis worked, and we're just waiting for the cough to go away."

The Houston Chronicle reported in February that Bush had been diagnosed with lower body parkinsonism, which causes a loss of balance, and that he often uses a wheelchair.

Bush, a Republican and the 41st president, took office in 1989 and served one term in the White House.

The father of former President George W. Bush, he also served as a congressman, U.N. ambassador, envoy to China, CIA director and was vice president for two terms under Ronald Reagan.

As president, Bush routed Iraq after former Iraqi President Saddam Hussein invaded Kuwait in 1990. His public approval ratings soared, but just 20 months later he was defeated in his re-election bid by Democrat Bill Clinton.

Until recently, Bush was known for an active lifestyle. He went skydiving to celebrate his 75th, 80th and 85th birthdays.

He met with former Soviet leader Mikhail Gorbachev this month in Houston. In March, Bush formally endorsed Republican Mitt Romney for president.