The children were 2 years old, 16 months and 2 months old.
Los Angeles County Sheriff's Lt. Dave Coleman said Wednesday that the mother, 30-year-old Carol Coronado, was hospitalized after being taken from the scene covered in blood and naked under a blanket, with multiple self-inflicted stab and slice wounds.
Investigators are examining her medical history.
Her husband was working on a car when the children's grandmother arrived and discovered the bodies.
Several knives were collected as evidence from the home.