A Westchester woman accused of suffocating her 4-year-old son has pleaded guilty to second-degree murder.

The Westchester County district attorney's office says 48-year-old Manuela Maria Morgado agreed Thursday to a sentence of 20 years to life. Her trial was to begin next month.

Morgado was arrested in 2012 after police found her with the body of her son, Jason Reish, in their Mamaroneck condo. She had apparently used helium and a pillow to suffocate him.

Police said Morgado was semi-conscious and may have tried to kill herself with a drug overdose.

The boy's parents, who never married and lived apart, had battled over where he should attend preschool. The district attorney said the killing was the mother's misguided attempt to keep the father out of their lives.