Lauren Coyle, 19, of Collins Road, Bamber Bridge, near Preston, pleaded not guilty to the unlawful killing of 19-month old Ellie May Minshull-Coyle at premises on Ward Street in Lostock Hall on March 23 last year.
Coyle appeared in the dock at Liverpool Crown Court alongside Reece Hitchcott, 19, of no fixed abode, and Connor Kirby, 20, of Octavia Court, Huyton, Liverpool - formerly Windrows, Skelmersdale.
Neither man is the baby’s father, the court was told.
The two men also denied manslaughter and the trio all denied causing or allowing the death of a child, and two counts of neglecting or ill treating a child between January 1 and March 23 last year.
Police were called to an address on Ward Street in Lostock Hall just after 9.30am on March 23 last year by paramedics who were treating the child.
Sadly, the little girl later died.
The three defendants were further remanded on unconditional bail to await their trial, which is listed to begin on October 2.
A pre-trial review for all three defendants is also listed for September 21l.