Pregnancy reaction generally refers to the reaction of pregnancy vomiting, the normal development of the fetus during pregnancy, pregnant women suddenly no reaction of pregnancy vomiting is also normal. Early pregnancy due to the body’s hormone content increases, resulting in nausea and vomiting, abdominal distension, anorexia greasy, loss of appetite, fatigue and other early pregnancy reaction, this is a normal physiological phenomenon. Most pregnant women will have early pregnancy reaction at about 6 weeks of pregnancy, and the early pregnancy reaction may gradually ease or disappear at 12 weeks of pregnancy. Therefore, if a pregnant woman suddenly has no reaction to pregnancy vomiting, but ultrasound examination reveals that the development of the fetus is normal, this is mostly considered to be a normal manifestation. If a pregnant woman suddenly has no reaction to vomiting during pregnancy, and ultrasound examination reveals that the fetus has stopped developing, this is not a normal phenomenon. Pregnant women who suddenly lose the reaction to pregnancy vomiting during pregnancy need to consult a doctor in time, if it is a normal phenomenon, there is no need for treatment. If the fetus stops developing, you need to choose the appropriate measures to treat it under the guidance of the doctor.