Eugenics four is very necessary to do, especially for some patients who keep pets at home or often contact with animals and pets, because in animals and pets are prone to parasites and viral infections. Usually when adults are infected with these conditions, there will be no special clinical signs and symptoms, but it will affect the fetus, for example, if the patient has an infection, there is a risk of stillbirth and miscarriage after pregnancy. If the fetus survives, fetal malformations may occur, especially the possibility of fetal intellectual problems is relatively high. If the patient has an infection during the pre-pregnancy eugenics test, as long as the patient is actively treated and cured, the pregnancy will generally not be affected.