If my baby has avsd what is the chance she has down's?

Other way around. About 1/3 of ds patients will have a heart defect including many with a vsd or other more complex defects. However, of all those with vsd the ds group is only a fraction of the larger number. Vsd's are relatively common & represent a failure in completion of the walls between the chambers that grow out from the side & knit together during fetal life. >1/2 will close on there own by a year of age.
No. Most babies with a heart defect do not have down syndrome. Babies who have down syndrome have a higher risk of having heart defects.