What is hyperemesis gravidarum? Pregnant women experience dizziness, lethargy, food selection, loss of appetite, mild nausea and vomiting during early pregnancy, which is called early pregnancy reaction. Early pregnancy reaction usually has little effect on life and work, and does not require special treatment, and mostly disappears naturally around 12 weeks of pregnancy. In a small number of pregnant women, early pregnancy reaction is serious, nausea and vomiting are frequent, and they cannot eat, which affects their health and even threatens their lives, so it is called severe pregnancy vomiting. The clinical manifestations vary greatly, and most patients are cured after treatment. Very few patients can die from certain complications, such as acidosis and liver failure, due to severe vomiting.