WASHINGTON – If President Obama and congressional leaders cannot come to an agreement on tax code changes in the coming weeks, some 562,000 low- and middle-class families in Massachusetts would lose access to the child tax credit, according to a new White House analysis.

Losing the tax credit would cost them an average of $1,000 annually in just one of the many ways that the looming austerity crisis would impact Massachusetts residents and businesses if politicians in Washington cannot come to terms on a deal before Jan. 1.