Thank You sir for prompt reply...........
Regards
Dear Jak,
Although this is a simple question, the answer is somewhat complex. The incidence of congenital cardiac defects is approximatley 0.8 to 1%. This means that 1 out of 100 to 125 babiies is born with a heart defect. We typically understand that the recurrence risk is approximately 2-5% for any defect for subsequent pregnancies. However, this may not be totally correct. If there is a genetic abnormality in one of the parents, such as DiGeorge syndrome, the risk of having a child with a heart defect may be significantly higher, depending on what the defect is. However, except for some syndromes, we do not know what the majority of these gene defects are, and do not screen for them, unless there is a strong family history of congenital heart defects.
We also know that certain defects, such as tetralogy of Fallot, can occur if the mother has not taken in enough folic acid (folate) early in pregnancy. Therefore, just like in the prevention of spina bifida, mothers who are planning on having a child should make sure that they are taking in adequate folate, even at the time of conception.
Finally, we believe that there are some heart defects that may be because of possible exposure to environmental contaminants. This is under further study, but may be a factor as well.