Please explain who is most at risk of giving birth to a child that has down syndrome?

Older moms: Risk for downs increses with maternal age. Hence, if you are over 35 years of age you have a much higher risk than a 25 year old. Of course amniocentesis can provide an accurate diagnosis; as well as soft signs on an ultrasound. Most ob-gyn docs will do an amnio if asked. Pts can then deicide if they wish to continue the pregnancy.

Varies: In most cases it is the 40+ year old for the traditional ds 21 trisomy @ 1/100 while over 45 would be 1/50. A woman that carries a balanced translocation (a piece of 21 swapped to another chromosome)could actually have a very high risk.Every ds baby should have chromosomes done.If a translocation is found (3%), the parents should be studied to define risk of recurrence.