The American economy expanded last quarter at the weakest pace in more than a year, depressed by the longest continuous homebuilding slump in a generation, economists forecast ahead of reports this week.

The Commerce Department will report April 27 that gross domestic product, the sum of all goods and services produced, grew at an annual rate of 1.8% in January through March, according to the median estimate in a Bloomberg survey of economists. That compares with a 2.5% gain the previous quarter.

Reports on housing and corporate spending for March may show a gain in momentum as the quarter ended, pointing to a pickup in growth.

“Housing will continue to be a major drag on the economy through the middle of this year and then it will lessen,” a senior economist at Wachovia Corp. in Charlotte, North Carolina, Mark Vitner, said. “We will probably see growth come back up a little bit this quarter and in the second half of the year.”

Spending gains have averaged 3.7% per quarter over the last decade.

“Consumption appears to have held up quite well, especially considering the steady escalation in prices at the gas pump over the course of the quarter,” the chief U.S. fixed income economist at Morgan Stanley in New York, David Greenlaw, said.