The hazards of eating a lot of junk food during pregnancy are mainly the following: First, junk food contains trans fatty acids, namely margarine or margarine, which are not easily removed after entering the blood vessels, and after eating it, pregnant women not only have a very bad effect on their own blood lipids, which can trigger the premature occurrence of atherosclerosis in the blood vessels of the whole body, but also through the placenta, which can cause certain harm to the heart and blood vessels of the fetus. Second, can cause obesity, because junk food contains high calorie and high sugar, high fat food, can lead to excessive maternal obesity during pregnancy, not only make pregnant women suffer from gestational hypertension and gestational diabetes risk factor greatly increased, but also can cause miscarriage, premature birth, stillbirth and fetal malformation incidence increased. Third, abnormal fetal development, due to junk food inside the fat and sugar is relatively more, while the protein content, trace elements, minerals, vitamins is relatively less. The lack of protein, vitamins, trace elements and minerals in the intrauterine environment during pregnancy will affect the healthy development of the fetus, which is very harmful to the fetal liver and kidney function and brain development. Fourth, abnormal behavior, after eating too much high-fat diet during pregnancy, the child will be born with increased mental and behavioral abnormalities, which can be manifested as anxiety, and there may be muscle weakness and other symptoms.