The federal prison guard who was impregnated behind bars by cop-killer Ronell Wilson is having contractions and could soon have the baby, her lawyer said yesterday.

Nancy Gonzalez, 29, was excused from a Brooklyn federal court date because she was awaiting transfer to a hospital, lawyer Anthony Ricco said.

She was arrested for having sex with Wilson at the Metropolitan Detention Center in Brooklyn and is expected to plead guilty.

“She is looking forward to . . . being a mother,” another one of her lawyers, Natali Todd, said.

Wilson was convicted of killing two undercover cops on Staten Island in 2003.