WASHINGTON — Housing starts in the United States rose far less than expected in March and factory activity in the mid-Atlantic region grew modestly this month, suggesting the economy could struggle to rebound from a soft patch in the first quarter.

The economy stumbled at the start of the year under the weight of a harsh winter, a resurgent dollar, weaker global growth and a labor dispute, which has been resolved, at the West Coast ports.

There are expectations that growth will rebound in the second quarter, but the lukewarm data on Thursday suggested the momentum would probably not be strong enough for the Federal Reserve to start raising interest rates before September.