"Previous reports have erroneously excluded fetuses that aborted or babies that delivered prematurely outside of the fetal surgery hospital, thus making fetal surgery appear as if it was beneficial," said Dr. Elaine St. John, associate professor of pediatrics at the University of Alabama division of neonatology, who was not involved in the study.
"The risk of prematurity is substantial and can't be ignored," said Dr. Noel Tulipan, director of pediatric neurosurgery at Vanderbilt, who has performed over 200 prenatal surgeries. "The challenge going forward is to devise ways to reduce that risks associated with the prenatal repair."
Still, Tulipan said mothers who qualify and who are informed of the risk should have the option since the benefits of prenatal surgery are becoming clearer.
Ten years ago, Katherine Mulligan, 40, of Cincinnati, learned through prenatal testing that her unborn son Sean had spina bifida.
"We went in for our well-baby ultrasound at 21 weeks, thinking that we were just going to get a checkup, and we got the news there," said Katherine Mulligan.
Desperate for a solution, the Mulligans turned to friends and researched information about treatments on the Internet.
"Word of mouth was probably the first way we found out," said Sean's father, Mike Mulligan. "Somebody said, 'You know, they're doing so many amazing things with fetal surgery now,' not knowing for sure if spina bifida was something that could be treated with fetal surgery."
A couple of weeks later, Katherine Mulligan underwent prenatal surgery at Children's Hospital in Philadelphia. But it wasn't until her son's birth that the Mulligans saw how well the surgery went.
"They could tell immediately that he had sensation in his toes. He could wiggle his toes," said Mike Mulligan.
The Mulligans said they were initially concerned because Sean was born prematurely. Sean, now age 10, can walk without the help of crutches or a wheelchair. While he still struggles with gastrointestinal issues, a common condition associated with spina bifida, Sean has far surpassed his family and even his doctor's expectations.
"That's the gratifying thing. Not statistics and all that sort of stuff, but seeing that kid – seeing the impact of that operation on that kid," said Adzick, who was Sean's surgeon. "I don't think it gets better than that."