explain what is the main cause for an abnormality child birth?

Question

abnormality mainly in the face and head

Answer 1

You need to talk to the mother's OBGYN. There are a multitude of things from genetics to drugs and alcohol to environmental pollutants to just pure awful luck that can cause such defects/ deformities. The only way to know why it happened to a specific child is to talk to the doctor that oversaw the pregnancy--if there was one. If not, talk to a specialist and the child's pediatrician.

Answer 2

could be anything from drugs, alcohol, fetal injuries to chromosones