The frantic situation occurred Wednesday inside a store in High Ridge, Missouri. Surveillance video showed the mother desperately trying to revive her baby.
The store’s manager called 911.
Abby Snodgrass, 17, heard the commotion from aisles away and ran to help, performing CPR. She had recently learned the procedure in her health class at Hillsboro High School in Hillsboro, Missouri.
“The one thought that crossed my mind was, ‘What if this doesn’t work?’ And I just had to push it out of my mind and keep going because I knew that’s what I had to do,” Snodgrass said.
Eventually the baby started breathing again.
“I can’t explain how happy I was when she started to breathe,” Snodgrass said. “It was a huge relief.”
Without the teen’s swift action, the infant may have died, emergency responders said.
Authorities said that the mother and child were doing well.
The baby's family released a statement to ABC News acknowledging Snodgrass's efforts.
"We are exceedingly grateful to the young woman who helped our daughter," the statement read. "Our daughter is home and healthy, and we couldn't be more thankful."