On Feb. 26, 2026, A University of California Davis Health research team has safely performed the world’s first spina bifida treatment combining fetal surgery with stem cells, according to results from Phase 1 of an ongoing clinical trial. These results have been published in The Lancet.

The study, called “Feasibility and Safety of Cellular Therapy for In-Utero Repair of Myelomeningocele (CuRe Trial): a First-In-Human, Phase 1, Single-Arm Study,” tested whether adding a layer of human placenta-derived stem cells to standard fetal surgery could be done safely. Spina bifida, also known as myelomeningocele, occurs when spinal tissue fails to fuse properly during the early stages of pregnancy. The birth defect can lead to a range of lifelong cognitive, mobility, urinary and bowel disabilities.

The first phase of the trial was funded by a $9 million state grant from the state’s stem cell agency, the California Institute for Regenerative Medicine (CIRM).

During fetal surgery, a small opening is made in the uterus. The surgeons then float the fetus up to that incision point so they can expose the back of the fetus and the spina bifida defect. The care team places a small patch containing living stem cells directly over the fetus’s exposed spinal cord, before closing the layers of the back to allow the tissue to regenerate. The stem cells, taken from donated placentas, are designed to protect the developing spinal cord from further damage before birth.

It is the world’s first in-utero stem cell therapy for spina bifida, and the only trial aimed at improving the outcomes for the children over fetal surgery alone.

Spina bifida affects 1,500 to 2,000 children in the United States every year. While fetal surgery has greatly improved outcomes since it was introduced more than a decade ago, many children still struggle with mobility and have other long-term complications. The CuRe Trial is exploring whether stem cells can add regenerative power to surgery, potentially improving mobility and quality of life.

The CuRe trial is now enrolling up to 35 patients in its Phase 1/2a study. Children will be followed through age 6 to evaluate long-term safety and early signs of improved movement, bladder and bowel function. The Phase 1/2a study is funded by CIRM and Shriners Children’s.