 Fetal surgery in utero before 26 weeks gestation has been performed with some hope that there is benefit to the final outcome including a reduction in Arnold–Chiari malformation and thereby decreases the need for a ventriculoperitoneal shunt but the procedure is very high risk for both mother and baby and is considered extremely invasive with questions that the positive outcomes may be due to ascertainment bias and not true benefit.Further, this surgery is not a cure for all problems associated with a neural tube defect.Other areas of research include tissue engineering and stem cell therapy but this research has not been used in humans.