Although ultrasound is an important part of prenatal diagnosis, it is not enough. However, prenatal diagnosis is not enough just to do ultrasound, which is only a screening test and not a diagnosis. However, we can follow the chart to do some laboratory tests, such as cord blood test, amniotic fluid test, etc., i.e., to perform prenatal diagnosis. For example, the ultrasound shows that the fetus has an extra finger. Is this just a fetal polydactyly or a combination of abnormal development of other organs and tissues? Or is it a genetic disorder with chromosomal defects in addition to an extra finger? These are things that ultrasound cannot tell us. At this point, we need to do a deeper examination. Clinically, there are two major misconceptions about ultrasound results One is that “there is a lack of follow-up examination of the causes of malformations.” Many pregnant women simply choose to abort after having ultrasound and learning that the fetus is malformed. They do not do prenatal diagnosis and post-miscarriage autopsy to investigate the root cause. This is likely to happen: the next baby the pregnant woman carries will still be unhealthy. In fact, many pregnant women who have recurrent spontaneous miscarriages have miscarriages due to fetal abnormalities or chromosomal abnormalities, but many are forced to accept the fact of miscarriage and do not choose to actively investigate the cause of the miscarriage. This is the approach of putting the cart before the horse. Secondly, when the ultrasound reveals a problem, the pregnant mother has a wish that the situation will get better the next time she comes for a follow-up ultrasound. For example, the ultrasound reveals a “dilated renal pelvis”. This phenomenon may disappear as the pregnancy progresses, but it would be a mistake to refuse to do prenatal diagnosis at this time because you think the fetus is fine. This is because the “dilated renal pelvis” is an important marker for chromosomal disease on ultrasound. The marker disappears, but the chromosomal disease does not disappear. Therefore, if some of the prenatal tests, such as ultrasound, reveal problems with the fetus and require further prenatal diagnosis, expectant mothers should not be reluctant to undergo the test for fear that the prenatal diagnosis may affect the fetus or even cause a miscarriage. If you compare the risk of having an abnormal baby with the possible risk of the test, you will be sensible enough to accept the doctor’s advice.