The victims were found inside the home on 161st Street just after 3:30 a.m. It isn't clear whether the day care center, called Mei Xin Care Incorporated, was licensed.
A 3-day-old and a 1-month-old both suffered stab wounds to their torsos. A 20-day-old baby has cuts on her chin, ear and lip.
The infants, all girls, were taken to local hospitals in critical but stable condition.
A female worker was also stabbed several times in the torso. A father of one of the babies heard her screams, intervened and was stabbed in the legs.
The female victim is in surgery for her injuries at New York-Presbyterian/Queens.
The suspect, a 52-year-old woman, was found unconscious in the basement with self-inflicted slash wounds to her wrist. Police said she worked at the birthing center
She is in police custody at New York-Presbyterian/Queens, where she is also being treated for critical injuries. Charges are pending, and a motive hasn't been determined.
Police recovered a butcher knife and a meat cleaver at the scene.
Nine babies, five girls and four boys, were in the house during the stabbings, and all of them were accompanied by parents. Part of the building houses living quarters and the rest appears to be a common nursery.
WATCH Friday morning's update by police