Washington (CNN) The Democratic advantage in the midterm elections among voters nationwide has narrowed since January, according to a Washington Post-ABC News poll released Monday.

Democratic candidates were favored to Republican candidates by 4 percentage points (47%) among registered voters in a generic congressional ballot -- down from a 12-point edge when the poll was last taken in January.

Among all adults, Democrats held a wider lead of 10 percentage points over Republicans in the generic ballot.

White voters showed an increasingly strong preference for the GOP in the poll. They opted for Republicans to Democrats by a 14-point margin in March, up from a 5-point difference in January.

The Post-ABC poll also showed a slight uptick in President Donald Trump's approval rating as well, with 40% approving and 56% disapproving of how he is handling his job. While Trump's approval rating ticked up from 36% in January, his majority disapproval rating remains historically high for a president in their second year in office.