Although media reports emphasize the accuracy of a new noninvasive prenatal screening test, raising expectations among expectant mothers, it does not definitively diagnose three types of chromosomal abnormalities, including Down syndrome, warned Haruhiko Sago, head of the Center for Maternal-Fetal and Neonatal Medicine at the National Center for Child Health and Development.

After months of postponement and discussions by medical experts, the Japan Society of Obstetrics and Gynecology released guidelines in early March to begin clinical trials on the test at limited medical institutions as early as April.

"It is not a definitive but yet a very high-performance test that can be used to avoid invasive tests such as amniocentesis. But this is not a test for all pregnant women," said Sago.