Researchers say they can reliably test for Down Syndrome much earlier in a pregnancy than before.

The New England Journal of Medicine reports a study of nearly 40,000 American women indicates the non-invasive test yields reliable results at 11 weeks after conception. The test, which combines a blood test and ultrasound, could be confirmed by a riskier, invasive test shortly afterward.

The development would allow women so inclined to seek an abortion in the first trimester rather than the second, when the medical risks are greater. It would also let women who want to give birth more time to prepare for a child with Down Syndrome, a leading cause of mental retardation.

Some ethicists have questioned any testing for Down's that leads to abortion, noting that many people with the syndrome lead happy, productive lives.