(LABELLE, Fla.) -- A virus infection Stephanie Connor acquired during pregnancy put her unborn daughter at significant risk for brain damage and lifelong hearing loss.
"It was traumatic," said Connor, of LaBelle, Fla., after learning about her daughter's condition. "It was like mourning the loss of a child."
At age 1, baby Madeleine was completely deaf in her right ear and her hearing was severely lost in the left, said Connor. While a hearing aid helped to amplify some sounds for Madeleine, it would never fully repair the damage in her ear.
But a simple experimental procedure that Connor enrolled in for Madeleine may have restored her hearing and reversed her condition.
In January 2012, Madeleine, now 2, became the first child to undergo an experimental hearing loss treatment through an Food and Drug Administration-approved trial at Memorial Hermann-Texas Medical Center that infused stem cells from her own banked cord blood into her damaged inner ear. Within the last six months, Connor says she's seen a dramatic improvement in Madeleine's ability to hear.
"Before, when she would hear something she would look all around," Connor said. "But now we notice that she turns in the right direction of the sound."
Madeleine was also able to speak for the first time, Connor said.
For more than two decades, umbilical cord blood transplantation -- either by a baby's own cord blood or another's, depending on the type of procedure -- has been used to treat otherwise fatal diseases including blood disorders, immune diseases and some types of cancers.
Infusing cord blood stem cells into the body may also have the potential to heal and regenerate damaged cells and tissues.
Regenerative therapy using cord blood stem cells is currently being studied as therapies to treat conditions including cerebral palsy and brain injury.
And for the first time, doctors are experimenting with cord blood stem cells to regenerate hearing in children who have suffered hearing loss.
This year-long study will follow 10 children, including Madeleine, ages 6 weeks to 18 months, who have acquired hearing loss and who have donated their cord blood to a registry.
Madeleine has already had one follow-up appointment to test her speech and language development, which are indicators that her hearing has improved. She will have another one mid-July.
Dr. Samer Fakhri, associate professor and program director in the Department of Otorhinolaryngology at Memorial Hermann-Texas Medical Center, and principal investigator of the study, said it's still too early to determine whether the procedure benefited Madeleine, or may be beneficial for other children.
Copyright 2012 ABC News Radio