Fetal venous catheterization is not seen twice, it needs to be rechecked regularly, but should be spaced out for a period of time, and other major screening tests are also needed. If it is the first trimester and no fetal venous catheter is found when doing the pregnancy test, or no signal of regurgitation of blood flow is seen, it is mostly a normal manifestation because the embryo is still small in the first trimester and cannot produce a signal in a short period of time, so regular checkups will usually be recommended but at intervals that are as far apart as possible. If no venous catheter is found during repeated tests, regular cardiac ultrasound is needed to understand the embryo’s heart development, and other major screening tests, including Down’s syndrome, amniocentesis, non-invasive DNA, etc., are also needed, so that the results of the tests can be synthesized to determine the embryo’s development. If accidental or poor embryonic development is found during the examination, there is a risk of fetal arrest, which needs to be handled in time, and the pregnancy should be terminated in time if necessary, which should be carried out under the guidance of professional physicians.