(CNN) -- When Kerry Higuera started bleeding three months into her pregnancy, she feared she was miscarrying. Heading to the emergency room seemed like the prudent thing to do.

Higuera says she'll regret that decision for the rest of her life.

When Higuera arrived at Banner Thunderbird Medical Center in Glendale, Arizona, that February morning in 2008, she was put in a room and told to wait for a nurse to come get her. Soon, a nurse poked her head into her room.

"She said, 'Kerry?' and I said, 'Yes,' and she said, 'I'm going to take you for a little walk' and I followed her down the hallway," says Higuera, a mother of four who lives in Peoria, Arizona.

"She brought me to the CT scan room, and I said, 'Is this really what I need to have done?' And the nurse said, 'Yes, this is what the doctor wants. He wants a CT scan of your abdomen,' and I said, 'OK,'" Higuera remembers.

After the scan, the nurse led Higuera back to a room to wait for the doctor.

"I was so scared. I told my husband, I'm sure I've had a miscarriage. I'm sure the doctor is going to come and tell us we lost the baby," she says.

But that wasn't what happened at all.

After about half an hour, Higuera says the emergency room physician, two radiologists and a representative from the hospital's human resources department came into her room.
"I started to cry and asked if I'd miscarried, and they said no, I was still pregnant. My husband and I said, 'Oh, that's great!'" she remembers.

But then they told the Higueras there was something else they needed to know. "They said, 'We made a mistake; we did something we shouldn't have done,' and I was like, 'What do you mean?'" Higuera remembers. "They said 'There's another patient here named Kerry, and you two are the same age. We mixed you up. She was supposed to have the CT scan, not you.' "

While no large studies have been done on the effects on the fetus of performing a CT scan to a pregnant woman's abdomen, experts say a fetus exposed to radiation can, in some cases, develop physical and mental growth problems