Police said the couple's baby boy was delivered prematurely at the scene of the accident early today in Brooklyn, New York. He was taken to a hospital in a serious condition.
Nathan and Raizy Glauber, both 21 from Willaimsburg, were taken to different hospitals where they were both pronounced dead.
The driver of the car they were travelling in is in a stable condition. They had booked a car service for the journey to a Manhattan hospital for their baby's birth.
Authorities said the driver and passenger of a BMW which smashed into the side of their vehicle at an intersection fled on foot. A search is underway and no arrests have yet been made.
Neighbour and family friend Isaac Abraham called it 'a tragedy beyond belief'
He added: "The child is in a serious condition in Beth Israel Hospital, in Manhattan. Now we just pray with the child that all medical efforts keep him alive."
Despite doctors' best efforts, Nachman and Raizy's baby boy sadly died on Monday. Isaac Abraham, a spokesman for the family's Orthodox Jewish community, confirmed the news to reporters.