TODAY | March 05, 2013
>>> back now at 8:36 with the story of a tiny fighter, a texas baby born with a rare condition that most newborns do not survive but no one counted on the spirit of a mother and daughter team destined to defy the odds. here is nbc's janet shamlian .
>> reporter: do i get a smile? it's a moment of pure joy every mother has experienced. hi, big girl . watching her baby reach a milestone, like that first smile. mommy was right. you like to smile. ashley cardinis knows when audrina accomplishes something it's nothing short of a miracle.
>> she lifts her body up. she 's wonderful . she's a wonderful little baby. look how little she is.
>> reporter: now 4 months old, she was born with half of her heart outside her body. it's called ectopiacardis and is almost always fatal.
>> most of those children don't live.
>> reporter: dr. charles frazier of texas children's hospital in houston says an ultrasound detected the condition early in ashley 's pregnancy.
>> i was devastated. didn't really understand what they meant by her heart was on the outside of her body.
>> reporter: surgery was the only hope. but there were no guarantees. 11 doctors would spend six hours trying to save audrina's life.
>> the actual chest cavity doesn't form in its proper sort of dimension. you can't just put the heart back in there and close the door .
>> reporter: there's no sternum, just skin and muscle covering the heart. the surgery is a success. finally, ashley could hold her daughter.
>> good. amazing. i don't want to put her down. she looked like a little baby. she looked like nothing was wrong with her. she was breathing fine.
>> reporter: but audrina is fragile. now out of the hospital, this shield protects her heart. she can't roll on her stomach without it. still on a feeding tube and oxygen, it is round the clock care. ashley will has 6-year-old twins. they will design a permanent cover for her chest. by the time she's in school she should be just like all her friends.
>> just the best baby anybody could ask for. smiling at all times, so i think she's going to enjoy life to the fullest.
>> a tiny fighter who is all heart and survivors come in many sizes. for "today," janet shamlian , nbc news, houston.