Non-invasive is not recommended for advanced maternal age because fetuses conceived in advanced maternal age have a greater likelihood of chromosomal abnormalities than normal pregnant women, and non-invasive DNA is not as accurate a diagnosis as amniocentesis.
NT test, Down screening and non-invasive DNA, which are routinely performed during pregnancy, are screening methods to detect chromosomal abnormalities in the fetus and cannot be used as a means of confirming the diagnosis. Amniocentesis can directly extract fetal DNA fragments for testing, to clarify whether the fetus has chromosomal abnormalities, compared with the above tests are more accurate, is to determine whether the fetus has chromosomal abnormalities of the means of diagnosis.
Compared with other mothers, the chance of chromosomal abnormalities in the fetus increases, so when chromosomal abnormalities are detected during screening, non-invasive DNA testing is usually not used, but amniocentesis is used directly to make the final diagnosis clearer.
Mothers of advanced maternal age must actively cooperate with clinicians to ensure the health of mother and baby.