Fetal skull defects that are relatively small can partially heal on their own, while those that are large or cannot heal on their own require cranial repair surgery. Whether a fetal skull defect can heal on its own depends on the severity of the skull defect. If the fetal skull defect is small, the defect can be healed by forming an island of bone and then forming a bone fragment. If the fetal skull defect is large, it can be treated with cranial repair surgery. Cranial defects can easily cause brain tissue damage, unable to maintain normal and stable intracranial pressure, such as fetal brain tissue bulging, etc., and in severe cases, can affect brain development, mental retardation or cerebral palsy, etc., which requires early and active intervention.