Linda Ackley, 44, had no idea she was pregnant when she went into Allegiance Health facility in Jackson, Michigan, US – but she delivered her first child the same day.
"Some people have nine months to prepare. I had 15 hours," her husband, Mike Ackley, told the local paper.
Linda went to the doctor because she had some bloating in her abdomen. Believing she might have a hernia, the doctor sent her to hospital for a computerised tomography or CT scan.
The scan revealed she was pregnant – and was full term – so the hospital immediately arranged a Caesarean section.
Kimberly Kay Ackley weighed 10lb 1oz.
The baby and her mother were discharged from the hospital four days later.
Looking back, Linda said she confused the baby's movements for expanding and contracting muscles and twitching nerves caused by her surgery.
"It never occurred to me I was pregnant," she said.
Her periods had always been irregular. She was not in pain and did not notice significant weight gain.
At the hospital, she and her husband of 24 years made phone calls, informing family members of the pending birth of their first-born.
They thought it was a joke, but Mike said. "Who can make this up?"