U.S. pending home sales fell 5.5 percent in April compared to the prior month, the National Association of Realtors said Wednesday, marking the weakest result in a year and raising more uncertainty surrounding the housing recovery.

Pending sales, which are based on contract signings that have not yet closed, were still up 14.4 percent compared to the prior year. The NAR expects existing home sales to reach 4.66 million units this year and 4.92 million units in 2013, up from 4.26 million units in 2011.

The month-to-month result missed the Reuters forecast of economists, who expected a slight increase in sales of 0.1 percent.