"I was definitely upset," she said. "I went through all the last how many months, thinking, 'Oh, I felt this,' and 'Maybe that is what this was' and 'Oh, why did I do that?'"
Dr. Ashley Roman, a clinical assistant professor at NYU School of Medicine and a specialist in high-risk pregnancies, said surprise pregnancies aren't so implausible after all.
"There really doesn't seem to be much scientific data on this topic, but I think if you were to poll every obstetrician, we've all seen it at some point in our career," Roman told ABC News in an interview last year. "We've seen the woman who comes in at term or near term and who didn't realize she was pregnant, and gives birth."
Roman said there are reasons a woman can carry a baby full-term and miss the signs.
"What's difficult, what many people say is, but how could you miss your growing belly? But some women tend to hide it well, their body just simply disguises it," she said. "They might chalk it up to the fact that they, maybe, they've put on a couple pounds and, 'I've gained weight for one reason or another.' There are a lot of ways to talk yourself out of this."
In addition to weight gain and, perhaps, denial, medical experts say factors like stress, dieting, a small or inactive fetus, obesity, a history of irregular cycles aor infertility or breakthrough bleeding during the pregnancy can also contribute to the "surprise pregnancy" phenomenon.
For Curry and her family, the trauma of the unknown pregnancy and surprise birth is just a memory, one now replaced by the joy of having another member of the family.
"Having Alex was a shock, but it was one of the greatest things in the world," she said. "We were overjoyed, and Tyler was overjoyed to have a new baby brother."
"He has taught me to not take anything for granted," she said. "Unfortunately, it had to be done in this way, but ever since he was in my life, I have had nothing but happiness and couldn't have asked for a better family."
The episode of "I Didn't Know I Was Pregnant," featuring Andrea Curry airs on TLC, tonight, Wednesday, Aug. 17, at 9:30 p.m., ET.