Threatened miscarriage refers to signs of miscarriage during pregnancy, and some women with threatened miscarriage may experience nausea. This situation includes several reasons: First, threatened miscarriage is not the same as a natural miscarriage; women are still pregnant, hence early pregnancy reactions such as nausea are normal. If the nausea is mild, rest and observation are advisable. However, if severe, it is important to visit the hospital for an examination to rule out hyperemesis gravidarum. Second, some cases of threatened miscarriage are caused by gastrointestinal inflammation, such as acute gastritis causing uterine contractions, which then leads to threatened miscarriage. The nausea in these situations is due to acute gastritis, so the nausea is a symptom caused by the condition that leads to the threatened miscarriage, not a direct result of the threatened miscarriage itself.