The search was suspended around 12:30 p.m. after about eight hours in which crews using helicopters and boats found nothing, Lt. Cmdr. Stephanie Brennell said.
Authorities have not been able to locate the woman who made the report, identified as Michelle Perez, of Camden, N.J., the Coast Guard said.
"It was basically an unconfirmed report that there were people in the water," Brennell said. "We didn't locate anybody during the searches. ... We don't have any other information to go off of."
The search began shortly after authorities got a call around 4 a.m. from a nurse at St. Joseph's Hospital in Philadelphia.
A woman had called the hospital and said she was in Camden, had just given birth and had thrown her newborn into the river from the Ben Franklin Bridge, the Coast Guard said.
The woman called back a second time and told another nurse she had also thrown her 4-year-old and 2-year-old children because she couldn't feed them, Coast Guard Petty Officer Michael Blake said.
The Delaware River Port Authority, which owns and operates the suspension bridge, said its security cameras didn't capture any images of a woman throwing anything off the span. It also noted that the pedestrian walkways are locked at night.
Peggy Boemmel, chief financial officer at St. Joseph's Hospital in north Philadelphia, said an alcohol and drug counselor received the call around 4 a.m. and kept the woman on the phone for a couple of hours while alerting another employee to call 911.
Boemmel was trying to determine whether the woman had ever been a patient there.
The Associated Press was not immediately able to locate a Michelle Perez in Camden.
Associated Press writer Kathy Matheson contributed to this report.