Amber Miller, 27, decided to run the Chicago Marathon even though she was 38 weeks pregnant, reports the Daily Telegraph.
She went into labour shortly after crossing the finishing line and gave birth to a daughter, June, later that night.
Mrs Miller completed the marathon in 6 hours, 25 minutes, while baby June weighed in at 7lbs 13oz.
She ran half of the race and walked the other half with her doctor's permission and her husband on hand for support.
Mrs Miller said she had run marathons while pregnant with her son Caleb, but never so close to term.
"I was kind of planning on running about half, and maybe skipping to the end and walking across the finish line," she told reporters at Central DuPage Hospital.Post published in: World News