It happened around 9:20 p.m. in the 1300 block of Lake Shore Drive.
Police were called to the area for a report of multiple gunshots.
Once there, officers found the victim, a 25-year-old woman, who had been shot in the right arm.
She told police she had been sitting outside when she heard gunshots. She ran into the home and only then realized she had been hit.
The woman, who is four months pregnant, was treated at Cooper University Hospital.
Police are offering a $500 reward for information leading to an arrest.
Anyone with information is asked to call the Citizen's Crime Commission at 215-546-TIPS (8477). Tips can be provided anonymously.