Vomiting in the middle of pregnancy is usually not a sign of fetal hypoxia, which is mainly manifested by abnormal fetal movement. Vomiting in the middle of pregnancy is generally considered to be caused by fluctuating hormone levels in the body, reduced secretion of gastric acid and delayed gastric emptying. Of course, many mid-pregnancy illnesses can also cause vomiting, such as gestational hypertension, pre-eclampsia, acute gastroenteritis and acute appendicitis. Further clarification is needed through associated symptoms and ancillary tests.