The woman was identified by her sister as 43-year-old Alayiah Hill.
She was shot seven times and underwent surgery at Penn Presbyterian Medical Center.
Her baby, five-month-old Yuri Weaver, was shot in the leg and taken to Children's Hospital of Philadelphia.
Both the mother and child are expected to survive.
Police said the shooting happened inside a second-floor bathroom of a home on the 1500 block of North Robinson Street around 4 a.m. Sunday.
Detectives are searching for 39-year-old Faheem Weaver, who the victim's sister said is the baby's father. She said she was home when the shots were fired.
"We were asleep, all you hear is boom boom boom, and I hopped up because I didn't know what the noise was, so I got up, went into the front room where she sleeps at, and she was bleeding. She said, 'He shot me.' And I said, 'Who?' And she couldn't say anything, she was just in shock," said the victim's sister, Amaryiah Mathis.
Mathis said her sister has had issues with him in the past.
"She was handling it like she should. It's being a good mom, doing what she needs to do for her daughter. But this is a lot," Mathis said. "My sister's a great mom. My sister works two jobs."
Police said they believe Weaver is driving a silver Toyota pickup truck with the Pennsylvania license plate ZSG-1977.
"From what I know, they still ain't found him," Mathis added. "They're looking for his car, so it's just a waiting game at this point."
Anyone with information on his whereabouts is urged to contact police.