What is the reason of chd in newborn?

Varies: Congenital heart disease is a complex group of defects that originate in abnormal decoding of the information used to form the heart. Some are a reflection of confusion when extra chromosome (cms) material is present or lost, like down or turner syndrome.Most reflect material on many cms that are linked is multifactorial inheritance. Recurrence risk 4% of some form of chd for future pregnancies.

No "reason": Chd occurs in a little less than 1% of births. Exactly why it happens is unknown.

Multiple factors: Congenital heart disease is present in 6-8/1000 live births. The cause of chd is unclear but involves both genetic and environmental influences. Many genetic syndromes are associated with chd (down syndrome, turner syndrome, vacterl association, etc). Maternal disease may also contribute (diabetes, lupus, rubella) as can some medications and alcohol. Usually the exact cause is unknown.