The Northwest Herald reports that Joann Cunningham gave birth to a girl on May 31.
The baby is being held in protective custody while both Cunningham and her ex-boyfriend Andrew Freund Sr. are being held in connection with AJ Freund's disappearance and death.
Cunningham, was charged with five counts of first-degree murder, four counts of aggravated battery, two counts of aggravated domestic battery, and one count of failure to report a missing or child death.
Andrew Freund Sr. was charged with five counts of first-degree murder, two counts of aggravated battery, one count of aggravated domestic battery, two counts of concealment of a homicidal death, and one count of failure to report a missing or child death.
The charges came days after Cunningham, who is seven months pregnant, made a plea for AJ's return to ABC News.
"I just want my kids, that's all I have. Those are my life, my kids," Cunningham said.
The boy was found six days after he was reported missing in a shallow grave, wrapped in plastic, Crystal Lake Police Department Chief Jim Black said Wednesday afternoon.
Police say the two killed the 5-year-old boy in their Crystal Lake home and then buried his body at a site in Woodstock.
WATCH: AJ Freund's body found 6 days after he was reported missing
AJ Freund body found after Crystal Lake boy missing 6 days; parents Andrew Freund, Joann Cunningham charged
WATCH: DCFS timeline of interactions with AJ Freund's family
AJ Freund's parents Andrew Freund, Joann Cunningham charged with murder after boy's body found
SEE INSIDE: Photos from AJ Fruend's home show filthy conditions
AJ Freund home photos from 2013 show filthy conditions
WATCH: DCFS releases full history with AJ Freund's family
AJ Freund's parents Andrew Freund, Joann Cunningham charged with murder after boy's body found
PREVIOUS COVERAGE
AJ Freund home photos from 2013 show filthy conditions
Andrew 'AJ' Freund's foster family releases statement: 'AJ was loved by us'
AJ Freund death: Parents of 5-year-old Crystal Lake boy appear in court Monday
Crystal Lake boy AJ Freund funeral arrangements announced; DCFS releases timeline, 2 workers reassigned
Two child deaths two years apart have DCFS back on hotseat
AJ Freund cause of death released, parents bond set at $5M each for Joann Cunningham, Andrew Freund, Sr.
How did Crystal Lake police crack the case of AJ Freund?
'He got a raw deal and God's going to fix it': Crystal Lake mourns AJ Freund after body found
Missing Crystal Lake boy AJ Freund's body found; parents Joann Cunningham, Andrew Freund Sr. charged
Missing Crystal Lake boy: 911 call reporting Andrew 'AJ' Freund, 5, missing, police history with family released
Missing Crystal Lake boy Andrew 'AJ' Freund: Father continues search, mother pleads for boy's, 5, return
Search continues for missing 5-year-old Crystal Lake boy, father vows own investigation
Crystal Lake community holds vigil for missing boy to "light the way for AJ"
Missing Crystal Lake boy Andrew 'AJ' Freund: Boy, 5, did not leave home on foot, police say
Crystal Lake boy missing: FBI joins search for 5-year-old Andrew 'AJ' Freund
RELATED: AJ Freund Crystal Lake missing person report: Police describe father as 'calm,' mother as 'frantic'