A new study sets the stage for wider use of gene testing in early pregnancy. Scanning the genes of a fetus reveals far more about potential health risks than current prenatal testing does, say researchers who compared both methods in thousands of pregnancies nationwide.

A surprisingly high number – 6 percent – of certain fetuses declared normal by conventional testing were found to have genetic abnormalities by gene scans, the study found. The gene flaws can cause anything from minor defects such as a club foot to more serious ones such as mental retardation, heart problems and fatal diseases.

“This isn’t done just so people can terminate pregnancies,” because many choose to continue them even if a problem is found, said Dr. Ronald Wapner, reproductive genetics chief at Columbia University Medical Center in New York. “We’re better able to give lots and lots of women more information about what’s causing the problem and what the prognosis is and what special care their child might need.”