Explanation:
The Central nerve system malformations which causes polyhydramnios are as follows -
1 . The baby born with an underdeveloped and malformed brain and skull , Anencephaly .
2. The Malformation in the development of the spinal cord , Spina bifida .,
3. The abnormal size of the cranium and the head .
4. The accumulation of the excessive fluid in the brain cavities , Hydrocephalus .
