If a pregnant woman is suddenly startled without causing any injury, the fetus will not be affected, but if she is seriously startled and suffers an injury, the fetus may be affected. Fetus in the amniotic cavity, the surrounding amniotic fluid can play a cushioning effect on the fetus, when a pregnant woman is suddenly startled, there may be a transient rapid heartbeat, shortness of breath, a sense of fear and other symptoms, usually in a short period of time will disappear, there is no fall, collision, the situation will not affect the fetus. Pregnant women who are suddenly frightened by a more serious, or even a heavier body collision, etc., will lead to accelerated heart rate, increased blood pressure, microvascular constriction, resulting in a decrease in the blood supply to the placenta, which may lead to intrauterine oxygen deprivation, affecting the normal development of the fetus, and in serious cases, inducing contractions, increasing the chances of fetal miscarriage or preterm delivery. Pregnant women who are suddenly startled if the body has abnormal symptoms of discomfort, we should consult a doctor for treatment in a timely manner in order to ensure the health of the patient and the baby.