(MCT) — WASHINGTON — During the debate over the 2010 federal health care overhaul, Democrats promised that illegal immigrants wouldn’t be among the 27 million people who’d gain coverage. President Barack Obama repeated that pledge last month when he outlined his immigration plan.

But while federal law generally bars illegal immigrants from being covered by Medicaid, a little-known part of the state-federal health insurance program for the poor pays about $2 billion a year for emergency treatment for a group of patients who, according to hospitals, mostly comprise illegal immigrants. Most of it goes to reimburse hospitals for delivering babies for women who show up in their emergency rooms, according to interviews with hospital officials and studies.