Prenatal surgery is better than postnatal surgery for myelomeningocele. In utero laparotomy to repair myelomeningocele, the most common type of spina bifida, improves the physical and mental development of babies, compared with corrective surgery after birth. The study, reported in the March 17 issue of the New England Journal of Medicine, was stopped early because differences between the groups were so stark. Prenatal surgery was performed before the 26th week of pregnancy. Twelve months after birth, only 40% of those in the prenatal surgery group needed shunts to divert fluid from the brain, compared with 82% in the postnatal surgery group. At the 30-month evaluation, children in the prenatal surgery group scored higher on tests of mental development than those in the postnatal surgery group, and 42% could walk without orthotics or crutches, compared with 21% in the postnatal group. Prenatal surgery probably benefits babies because it permits more normal nervous system development prenatally.