The $15 million, eight-year study found that the screening, which combines a blood test with an ultrasound exam, can pinpoint many fetuses with the common genetic disorder 11 weeks after conception.
Such screening before the second trimester allows women who might opt to terminate a pregnancy to make that decision when doctors say an abortion is safer and less traumatic, the Washington Post said.
"This is a big deal for women. It's going to have a big impact on care for women, not just in the United States but throughout the world," said Fergal Malone of the Royal College of Surgeons in Dublin, who led the study published in the New England Journal of Medicine.
However, Gene Rudd of the Christian Medical & Dental Associations said he was concerned that screening could be used to try to eliminate babies with Down syndrome.
Down syndrome is the most common major chromosomal abnormality, occurring in about one in 800 births.