Officers were called at 12.15pm on December 16 and attended the scene on Norman Crescent in Rossington, alongside the ambulance service. Sadly, the baby was pronounced deceased at the scene.
Two women, aged 17 and 45, were arrested on suspicion of murder and remain in police custody at this time.
Temporary Superintendent Jamie Henderson said: “This is an extremely tragic case and I know the local community, and those further afield, will be very upset to hear about what has happened.
“At this time, our investigation into the circumstances surrounding the baby’s death is in the very early stages and we ask the public not to speculate about the case.
“There is a cordon in place on Norman Crescent while our officers carry out their work, and therefore we are asking members of the public to avoid the area at this time.”