Those seeking encouraging news about the first quarter could find it in separate reports on Friday. The Labor Department said an index reflecting labor costs had its best showing in almost a decade, indicating that falling unemployment and faster hiring is translating into better wages — something notably absent in the recovery until recently.

Reaffirming its recent findings, the University of Michigan said its consumer sentiment index finished April with a decidedly bullish reading of 97, up from 87.2 just before the election.

The White House provided a statement saying the report on gross domestic product might have been influenced by seasonal factors, but “shows that we still have work to do to get the economic growth President Trump wants and expects.”

And in an interview with Fox News on Friday, Mr. Trump said that, with better trade deals, the United States should be able to lift the rate of economic growth to 5 percent or more in a few years.

With personal consumption accounting for nearly 70 percent of all economic activity, however, the administration will be hard pressed to lift growth substantially if consumers remain cautious about opening their wallets.

Jason Furman, chairman of the Council of Economic Advisers under Mr. Obama, said he found the disconnect between findings of optimism and actual behavior puzzling, though he added, “It’s possible it was a blip.”

On the other hand, something more significant may be happening. The rising cost of necessities like health care, housing and education is crowding out discretionary spending for middle-class Americans, said Stephanie Pomboy, founder of MacroMavens, an independent economics consulting firm in New York.