The crash occurred around 2:40 a.m. Tuesday at the intersection of Haverford and Overbook avenues.
Police say a man and a pregnant woman in a 2006 Chevrolet pickup truck were stopped at a traffic light when they were rear-ended by a 2003 white Lexus.
Arriving medics took the man and woman to Lankenau Medical Center where the woman gave birth.
Action News is told the baby was due in May.
The 42-year-old mother and 36-year-old man are in stable condition.
The 56-year-old Lexus driver was arrested for DUI and driving with a suspended license.
The investigation lead to the closure of Haverford Avenue.
The investigation is ongoing.