For decades, conventional wisdom held that pregnant women thirty-five and older were the only ones who needed testing for Down syndrome. But that’s changing.

The American College of Obstetricians and Gynecologists is now recommending screening for all pregnant women, regardless of age. The change was prompted in part by the availability of new, less invasive testing methods, including an ultrasound that can detect risk as early as eleven weeks into pregnancy.

But the organization is also recommending that the option of more invasive procedures, such as amniocentesis, should be made available to all pregnant women. The guidelines discuss the advantages and disadvantages of each screening test and some of the factors that should be weighed, including the age and number of fetuses, family history and the availability of various tests.

Screening tests estimate the risk that a fetus has Down syndrome, while diagnostic tests can tell whether the fetus actually has the condition. Down syndrome is a common disorder caused by an extra chromosome and can result in congenital heart defects and mental retardation. The risk of conceiving a child with Down syndrome increases with age, from one in twelve-hundred-fifty at age twenty-five to one in one-hundred-six at age forty.

Not everyone is enthusiastic about the new recommendations. The National Down Syndrome Congress issued a statement expressing concern, saying the screenings could produce numerous false positives, which may cause unnecessary distress and termination of pregnancies.

Looking for more information? Visit the A-COG’s Web site at www.acog.org.