Fetal harelip is a congenital cleft lip and palate that forms mostly during the first two months of pregnancy. It may be related to the following reasons: 1. Genetic factors: If there are patients with cleft lip and palate in the fetus’ relatives, the probability of this disease occurring in the fetus will increase, and it has a certain heredity. 2, environmental factors: exposure to radiation and environmental pollution during pregnancy, such as pesticides, fertilizers, home renovation and other situations may lead to fetal malformations. Try to stay away from pollution and radiation during pregnancy preparation. 3, folic acid deficiency: vitamin deficiency caused by anorexia after pregnancy can also cause fetal dysplasia, pay attention to diet after pregnancy to correct folic acid deficiency in a timely manner. 4, the pregnant woman’s own problems: pregnant women after pregnancy cold, or taking certain drugs, and a long time of anger and other bad emotions may cause genetic mutations occur cleft lip and palate and other malformations. Keep your mood comfortable after pregnancy, and treat colds under the guidance of your doctor. A reliable diagnosis of cleft lip and palate can be made during pregnancy when the ultrasound can clearly show the soft tissues of the fetal face. Most of them are detected during the grand mal ultrasound examination at 20-26 weeks. Folic acid supplementation before pregnancy and regular maternity checkups during pregnancy are necessary and must be standardized.