B ultrasonic to exceed what damage to the fetus whether, in the medical field, it has not yet authoritative, is the debate, most scholars think B ultrasonic examination to the fetus has no sure of damage. From B ultrasonic to exceed the principle analysis, B ultrasonic ultrasonic transmission is, there is no ionizing radiation and electromagnetic radiation, is a sound wave transmission, the sound waves to the human body organization is not anything to hurt. But if the sound waves in a fixed place dense, and gathered together a long time, it will be a heating, the heating effect to a certain extent, to human tissue may have a bad effect, the influence of the cell substances, including chromosomes.

Theory is of high strength of ultrasonic can through its high temperature and the role of the organizations cavity, damage to the organization. But in fact, the medical use of B ultrasonic super is low intensity, less than 94 mw/cubic centimeter, it is not a risk to the fetus, is still not B ultrasonic ultrasonic examination cause fetal malformation reports. At present, all the hospitals in a maternity used in the field of fetal B ultrasonic examination is safe. But that does not mean that in the whole pregnancy can optionally be doing B ultrasonic to exceed an examination, and have no time and the limited times. Scholars have made such experiments, the 11 to 12 weeks of fetal eyes and cornea for B ultrasonic to exceed the lens irradiation, find no to illuminate, didnt have any effect, illuminate five minutes, corneal or lens have mild edema, illuminate ten minutes, swelling degree is illuminate five minutes of heavy some, but reversible, stop after irradiation can be back to normal. If irradiation time more than twenty minutes, change is not reversible.