The Eurozone economy grew at more than twice the pace of the United States in the first quarter, according to preliminary estimates, as extraordinary stimulus from the European Central Bank and a weakening currency combined to boost growth.

GDP growth for the 19 member states using the single currency was tabbed at 0.5% for the first three months of the year, according to the region's official statistics office, Eurostat. That puts the bloc's annualized growth rate of 1.8%, a pace that leaves both the U.S. (0.7%) and the U.K. (1.2%) trailing in its wake.

Market reaction to the data, however, was largely muted, with the single currency holding at around 1.0911 against the U.S. dollar and benchmark 10-year German bund yields, a proxy for the region's borrowing costs, falling 1 basis point to 0.32%.

"It's true that growth is improving," ECB President Mario Draghi told reporters last week after the Bank's most recent interest rate decision. "Things are going better. And you remember in 2013 we were speaking of a recovery which was fragile and uneven, and now it's solid and broad."

Eurostat's initial estimate, however, is subject to significant revisions given that the agency altered its reporting procedures last year in an effort to post data 30 days, as opposed to 45 days, from the end of the previous quarter. 

"As flash estimates are available earlier than the traditional estimates, there is a trade-off between timeliness and accuracy," Eurostat said when the changes were first announced. "Based on the 16 test estimates, the expected typical revision for the GDP growth rates (with one decimal rounding) would be -0.1, 0.0 or +0.1 percentage points for both the euro area and the EU."

The next, more detailed preliminary estimate will be published on May 16.