UC Davis researchers conducted the first human study to test the safety of stem cell treatment for spina bifida during prenatal surgery.[1] The study included six pregnant women whose fetuses were diagnosed with myelomeningocele—the most severe form of spina bifida.[3] During standard fetal surgery, surgeons applied placenta-derived mesenchymal stem cells directly to the exposed fetal spinal cord.[3] All six newborns born between July 2021 and December 2022 had intact, healed spinal repairs with no signs of infection, abnormal tissue growth, or tumor formation.[1][5] MRI scans after birth confirmed that the brain abnormalities associated with spina bifida (brainstem herniation) had fully returned to normal in all children.[1][5] The study did not report any safety concerns related to the stem cells or any serious adverse effects during the observation period.[1][5] Children will be monitored until age six to confirm long-term safety and improve mobility and quality of life.[5]