A spokesperson for the police said she had slashed her wrists.
The victims were taken to local hospitals, and one of the children is in serious condition, but none of the injuries are expected to be life-threatening.
NY reports that authorities say the stabbings happened just before 4am on Friday.
The two adults injured a dad of one of the kids and a member of staff at the daycare centre.
There were five baby girls, four baby boys and some of their parents inside when the stabbing took place at 3.40am. The infants are in critical but stable condition at area hospitals. Her relationship to the victims has not been disclosed so far.
According to police, the woman stabbed three infants - two girls and one boy.
There is no record for any business at that site online.
This was the scene later in the morning as it became light.