<P> Non-invasive techniques include examinations of the woman 's womb through ultrasonography and maternal serum screens ( i.e. Alpha - fetoprotein ) . Blood tests for select trisomies ( Down syndrome in the United States , Down and Edwards syndromes in China ) based on detecting cell - free placental DNA present in maternal blood , also known as non-invasive prenatal testing ( NIPT ) , have become available . If an elevated risk of chromosomal or genetic abnormality is indicated by a non-invasive screening test , a more invasive technique may be employed to gather more information . In the case of neural tube defects , a detailed ultrasound can non-invasively provide a definitive diagnosis . </P>
<P> Non-invasive techniques include examinations of the woman 's womb through ultrasonography and maternal serum screens ( i.e. Alpha - fetoprotein ) . Blood tests for select trisomies ( Down syndrome in the United States , Down and Edwards syndromes in China ) based on detecting cell - free placental DNA present in maternal blood , also known as non-invasive prenatal testing ( NIPT ) , have become available . If an elevated risk of chromosomal or genetic abnormality is indicated by a non-invasive screening test , a more invasive technique may be employed to gather more information . In the case of neural tube defects , a detailed ultrasound can non-invasively provide a definitive diagnosis . </P>
which tests are noninvasive and performed to detect chromosomal abnormalities in the fetus
which tests are noninvasive and performed to detect chromosomal abnormalities in the fetus
ultrasonography maternal serum screens non-invasive prenatal testing ( NIPT )
ultrasonography maternal serum screens non-invasive prenatal testing ( NIPT )