The couple's baby was delivered after the wreck, but died a day later.
DA Charles J. Hynes announced the new charge Tuesday against Julio Acevedo. He previously was charged with leaving the scene of an accident.
Police say Acevedo was speeding on March 3 before crashing into the hired car carrying Nachman and Raizy Glauber.
The defendant was later arrested in Bethlehem, Pa.
His family has described Acevedo as a loving, stay-at-home dad. His lawyer says it was a tragic accident and not a crime.