How can a woman give birth to a baby without even knowing she's pregnant?
It seems impossible, but Jennifer West knows otherwise. Her son, Robbie, now three years old, was conceived while she was on the pill. Throughout the pregnancy, she had no clue she was carrying a baby.
"That was honestly the furthest thing from our minds at that point," said Jennifer's husband, Dan West.
Then one day, while vacationing in their remote Wisconsin cabin, Jennifer started having stomach pains.
"I really wasn't feeling well," she said. "I just thought, 'I have the flu or something.'"
As the pain got worse, though, Jennifer was convinced something was seriously wrong.
"I went from feeling bad to feeling horrible. I literally thought I might die in this cabin," she said.
Dan rushed his wife to the nearest emergency room, where the nurses immediately suspected she was pregnant and performed an ultrasound.
Jennifer and Dan were incredulous. "I thought I was dying from a tumor," Jennifer said.
But it turned out that she was in labor, and two hours after arriving at the hospital, Robert Heyward West was born.
In a second case, Jessica Kosciuszko, 24, was working two jobs and planning her wedding when she felt sick one day.
"I had extreme stomach problems, cramping, diarrhea, and I started dry-heaving and I thought, 'Oh, this is bad,'" Jessica said.
She had missed a few periods, but two pregnancy tests had come back negative.
"Me and my fiancé talked a lot about having children. We knew we wanted to wait at least a year or two," Jessica said.
But fate had other ideas. Convinced she was desperately ill, her fiancé Ben rushed her to the emergency room. A nurse felt Jessica's stomach and immediately knew the truth.
Jessica had gained no weight, had no symptoms or any prenatal care for nine months, but the baby was coming.
"[The nurse] said, 'Honey, you didn't know?'" Jessica said. "And I said no. And you could tell she was scared at that point because she didn't know how far along I was, if it was a full-term baby, a premature baby, they had no clue."
Fifteen minutes after Jessica entered the emergency room, little Alexis Barbara was born. Two weeks later, Ben and Jessica got married as planned, but with one more guest at the wedding.
"I think by Alexis coming into our lives, it was that ray of sunshine that we all needed," Jessica said.
It is extremely rare for a woman to not know she's pregnant, but it could happen if a woman is overweight or does not have regular periods, said Dr. Kristin Bendikson, an assistant professor of obstetrics and gynecology at the University of Southern California.
"For example, you can have a young woman that has a condition called polycystic ovarian syndrome, or an older woman who is going through her perimenopausal transition. These women may not have cycles frequently," Bendikson said.
How could a woman not feel a baby kicking and moving around?
"Well, if you don't think that you're pregnant and you don't think it's a possibility, these women may have attributed the symptoms and signs of pregnancy to other things like, for example, stomach issues," Bendickson said.
There are obvious dangers to the mother and the child if a woman doesn't know she's pregnant.
"For the mother, you'll miss out on screening of medical conditions such as diabetes or pregnancy, blood pressure, the mother may be taking medications or have problems that may impact the baby's health during the pregnancy," Bendickson said.
Luckily, both Jennifer and Jessica's babies were born healthy.
The documentary, "I Didn't Know I Was Pregnant," will air on the Discovery channel July 29 at 9 p.m.