Perinatal complications
Apart from genetic mutations discussed above, the natal period is very crucial phase for proper development of the fetus. Any disturbance of the normal in this stage can leave lasting effects on the fetus. Some common disturbances at this stage include infections suffered by the mother. Poor oxygen supply to the fetus due to various reasons can also impede proper development of neural tissue. Poor nutrition of the mother during pregnancy, which can then pose threat of poor blood supply or ion imbalance.