Fetal surgery’s benefits need further study: report
A survey of research on maternal-fetal surgery has found that there is not enough information to reach definitive conclusions to guide care.
The report, titled “Evidence to Inform Decisions AboutMaternal-Fetal Surgery,” was prepared by the Vanderbilt Evidence-Based Practice Center. Results were published in the journal Obstetrics & Gynecology in tandem with the release of a technical brief funded by the federal Agency for Healthcare Research and Quality's Effective Health Care Program.
The investigators surveyed research on the surgical repair of abnormalities in fetuses in the womb in seven conditions: congenital diaphragmatic hernia, cardiac malformations, myelomeningocele, obstructive uropathy, sacrococcygeal teratoma, twin-twin transfusion syndrome and thoracic lesions.
Of the 166 studies identified, only three were randomized clinical trials. The majority were case series, which are observational reports without enough basis for comparisons and outcomes, the report said.
Katherine Hartmann, M.D., Ph.D.
“Fewer than 4,500 infants total have been studied,” said Katherine Hartmann, M.D., Ph.D., director of the Vanderbilt Evidence-Based Practice Center and an investigator on the study.
“Most areas of medicine that would find those numbers unacceptable. Our abilities have gotten ahead of the research. How can we be offering a spectrum of high-tech surgical interventions with only three randomized trials?”
The most common outcomes measured were survival to birth, preterm birth, and neonatal death. Reporting on long-term outcomes for infants was rare. Forty-seven studies followed cases only to birth, 35 studies followed less than 6 months after birth, and 25 did not report length of follow-up.
Reports of maternal outcomes also were rare, particularly those related to future reproductive function.
Hartmann said research into maternal-fetal surgery is lacking not because of small patient populations prohibiting research, but because of conflicting emotions related to care.
From left, Noel Tulipan, M.D., Kyle Mangels, M.D., and Joseph Bruner, M.D., perform surgery on a fetus with spina bifida at Vanderbilt University Medical Center in 1998. (photo by Anne Rayner)
“Fetal surgery is a particularly difficult situation because referring physicians want to provide the best care, parents are desperate for answers, and some surgical centers are actively marketing these services and offering hope for improved outcomes when the literature is inconclusive,” Hartmann said.
“There is a lot of gut instinct that fixing it early has to be better, and layered on top of that is mothers who don't want to be in a randomized trial with the chance they may not receive surgery. There can be pressure from multiple parties to do everything possible.”
For an example of research done right, Hartmann points to the Management of Myelomeningocele Study (MOMS), a seven-year, multi-site National Institutes of Health trial performed at Vanderbilt that demonstrated clear benefit for babies who undergo fetal surgery to treat spina bifida.
“The MOMS trial was unique because to participate, Vanderbilt had to agree to do no surgery outside the trial. That was a major risk to the surgical program, but is the only way to get high quality data,” Hartmann said.
She also points to the contributions of groups like International Fetal Medicine and Surgery Society, the North American Fetal Therapy Network, and the International Fetal Surgery Registry, for advancing maternal-fetal surgery research.
“Ultimately the technology has outpaced the data,” Hartmann said. “Without enough research, our ability to provide information to help people make informed decisions is impaired.”