Trish Staine thought the aches and pains of a two-hour run were just one hazard of training to run a half-marathon. But Staine's soreness was instead a sign that she was in labor.
A day after completing a two-hour run along a hilly road, Staine was admitted Monday to the Essentia Health-St. Mary's Medical Center in Duluth, Minn., with severe pain in her back. Emergency room doctors told Staine and her husband that she wasn't injured, she was about to have a baby.
"They found a fetal heartbeat and I was like, 'No, that's not possible,'" Staine told ABCNews.com affiliate WDIO-TV. "They rushed me upstairs and within five minutes of getting into my room, she was born."
Staine's baby girl, named Mira, short for Miracle, according to The Associated Press, was born five weeks early at a healthy weight of 6 pounds and 6 ounces. Staine and her husband were completely surprised by the birth because she had not gained significant weight or missed periods.
"I've always been skeptical about all these TV shows and whatnot with people saying, 'Oh, I didn't know I was pregnant,'" Staine told WDIO-TV. "I'm like that's impossible. … As soon as I had her, I was like, 'I'm a believer.'"
Although it is rare to a have pregnancy undetected until birth, Dr. Shilpi Mehta-Lee, assistant professor of Obstetrics and Gynecology at the NYU Langone Medical Center in Manhattan, said that according to studies, about 1 in 2,500 births are not detected until the baby is delivered.
Mehta-Lee, who did not treat Staine, said that some women have difficulty psychologically accepting they are pregnant, which can result in a medical condition called "'denial of pregnancy." She cautions, however, that some women do not realize they're pregnant simply because they display no traditional symptoms of pregnancy.
"This [story] is a great opportunity to step back and say I haven't gotten my period or my period is irregular," Mehta-Lee told ABCNews.com of other women who might be missing the signs of pregnancy. "It's never too late. Better to initiate [prenatal] care 20 or 30 weeks [into a pregnancy] than never initiating care."
In addition to baby Mira, Staine and husband John have two biological children of their own, plus John's two sons from a previous marriage and two foster children. Trish Staine said there was one member of the family who was particularly excited about the new baby: her older daughter, 7.
"My daughter is really happy, she finally has a little sister," Staine told WDIO-TV. "She's the only girl. Now we have two girls and whole team of boys."