Older women who become pregnant face the possibility that their baby will be at higher risk for conditions like Down Syndrome or congenital heart defects. Until recently, amniocentesis -- involving a large needle inserted into the woman's belly -- has been the primary option to test for such conditions in a fetus.

But evolving ultrasound technology called "nuchal transparency" allows ultrasound technicians, or sonographers, to check for the presence of a pocket of fluid at the back of the baby's neck that indicates fetal abnormalities. The procedure can be conducted during the first trimester of a pregnancy and may preclude the need for amniocentosis, which entails some risk of fetal trauma and infection for the woman and cannot be conducted until four or five months into a pregnancy.

Nuchal transparency has been performed in the U.S. since 1995, mostly at large medical centers, but is becoming widely available as more sonographers and physicians acquire training and certification to conduct the test.