Michele Kalina, 44, of Reading is set for a combined plea and sentencing hearing on June 2, court records show.
Investigators believe the home-health aide secretly gave birth to five babies conceived through an extramarital affair with a co-worker, and immediately killed them.
She gave birth to a sixth child of his in a hospital in 2003 and put the girl up for adoption, authorities said. The boyfriend was unaware of the pregnancies.
Kalina is married and has a teenage daughter, and had a disabled son who died of natural causes in 2000 at age 13.
Berks County District Attorney John Adams and public defender Holly Feeney each declined comment Friday, citing a gag order.
The proposed plea agreement has not been filed and it's not clear what charges Kalina will admit, or if the defense will raise mental-health issues. She was charged in August with one general homicide count and multiple counts of abuse of a corpse and concealing the death of a child.
The plea may not end the many mysteries surrounding the case, including where Kalina gave birth, why she delivered the one child at a hospital and why she kept the infants' remains, even when her family moved across town.
One set was buried in cement and the others in a cooler, a plastic tub and a cardboard box.
After the family moved into a high-rise apartment near the county courthouse, she kept the containers in a locked closet, with strict orders that her husband and daughter keep out, according to a police affidavit.
But curiosity got the better of the 19-year-old daughter one night last summer when Kalina was out. She made the gruesome discovery, and called police.
The officers thought they were merely animal remains. But they were called back later that day, July 29, when the other sets of remains were found.
Kalina has been in custody since her arrest on the lesser charges a few days later. The homicide charge was not filed until extensive testing to determine whether the babies were born alive, and to whom.
DNA tests revealed the boyfriend fathered at least three and possibly four of the five slain infants; there was not enough material from the fifth set to test. The size of the bones suggests the infants were born at or near term.
"I think she was hiding them because they were from the boyfriend," Assistant District Attorney M. Theresa Johnson, the lead prosecutor on the case, told The Associated Press last year. She did not return messages Friday.
Jeffrey Kalina had wondered at least once if his wife was pregnant. And Kalina had explained to the boyfriend that she had abdominal "cysts" she sometimes needed to have drained. They started dating in 1999, and she became pregnant a short time later.
The boyfriend has not been identified, but Johnson previously described him as "overwhelmed and shocked" by the news.
He wants to give the infants a proper burial when the criminal case is over, authorities have said.