By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) - Amniocentesis is the classic way for detecting chromosomal abnormalities in a fetus and requires an invasive procedure to obtain amniotic fluid. An even more invasive approach is obtaining a small part of the placenta.

There is some very interesting information from the American Journal of Human Genetics where researchers report being able to find subchromosomal fetal mutations in a sample of the mother’s blood – with no invasive procedure needed.

It should be stressed that the current practice of amniotic fluid or chorionic villi sampling is generally considered safe, but it does carry a small risk of miscarriage or infection and any opportunity for less invasive procedures in any test is a great idea.