For the first time in history, surgeons applied live stem cells directly onto the damaged spinal cord of an unborn baby — and the results have exceeded every expectation.
A Phase 1 clinical trial at UC Davis Health, published in early 2026, has shown that combining traditional fetal surgery for spina bifida with the application of placenta-derived mesenchymal stem cells (PMSCs) is not only safe, but yields outcomes that have left the medical community quietly astonished.
What Is Spina Bifida?
Spina bifida is a birth defect where the spinal column fails to close completely during fetal development. The most severe form — myelomeningocele — leaves part of the spinal cord exposed outside the body. Without intervention, affected children typically face paralysis below the lesion, chronic hydrocephalus (fluid on the brain) requiring a permanent shunt, and varying degrees of bowel and bladder dysfunction.
Fetal surgery to close the spine before birth — performed while the baby is still in the womb — has been available for over a decade, and it improves outcomes compared to postnatal repair. But the underlying nerve damage was always considered irreversible.
The UC Davis team asked: what if we could do more than close the wound?
The CuRe Trial
The CuRe Trial (Cellular Therapy for In-Utero Repair) enrolled six unborn babies diagnosed with myelomeningocele, whose surgeries were performed between July 2021 and December 2022. During each procedure, surgeons applied PMSCs — stem cells harvested from the baby's own mother's placenta — directly onto the exposed spinal cord before closing the wound.
The stem cells had been shown in animal studies to reduce inflammation, support nerve regeneration, and promote healing. This was the first time they had been used on a human fetus.
The Results
The outcomes were, in the researchers' own careful scientific language, exceptional:
- Zero safety concerns. No infections. No spinal fluid leaks. No abnormal tissue growth. No tumours. All surgeries successful. All wounds healed completely.
- Hindbrain herniation reversed in all six infants. This brain abnormality — which in spina bifida typically causes the lower part of the brain to push down into the spinal canal — was observed on post-birth MRI scans to have reversed in every child in the trial.
- No baby required a brain shunt before discharge from hospital. In standard care, a significant proportion of spina bifida babies require shunts. In this trial: none.
"The early results are really exciting," said the UC Davis team. "We're cautiously optimistic that this approach could improve outcomes in ways we haven't been able to achieve before."
What Comes Next
Long-term follow-up of the original six children is ongoing — they will be monitored until the age of six to assess motor function, bladder and bowel control, and neurological development.
But the results were strong enough that the FDA and an independent safety monitoring board have approved moving to Phase 2 — an expanded study involving 29 participants.
This is science doing what science is supposed to do: taking a problem once considered fixed, and finding a way through it.
Six children were born into a world where doctors had found something new to give them. That is not a small thing.
Sources: The Guardian (Feb 26, 2026) · UC Davis Health · Gizmodo · Healthcare in Europe · Shine Charity · The Lancet (Phase 1 published results)
