Most of the pregnancy reactions appear around 6 weeks of pregnancy, some sensitive pregnant women may appear at 4 weeks, but most pregnant women have relatively obvious symptoms of pregnancy vomiting at 6-8 weeks of pregnancy. Early pregnancy reaction is related to psychological factors, increase of HCG in the body, gastrointestinal dysfunction, decrease of gastric acid secretion and prolonged gastric emptying time. Therefore, the start time, degree and duration of early pregnancy reaction vary from person to person. Most pregnant women can feel nausea and vomiting at 6 weeks of pregnancy, which is mainly related to the level of chorionic gonadotropic hormone in the body. A small number of pregnant women start to experience vomiting at around 4 weeks of pregnancy, while some do not experience vomiting throughout their pregnancy. In general, the symptoms of pregnancy vomiting are relatively obvious between 6 and 8 weeks of pregnancy, and are most severe between 8 and 10 weeks, and disappear on their own around 12 weeks of pregnancy. After the onset of pregnancy vomiting, pregnant women should pay attention to ensure sufficient rest, pay attention to diet regulation, appropriate exercise, and adjust their emotions. If you are diagnosed with hyperemesis gravidarum, hospitalization is recommended.