Hyperemesis gravidarum usually appears after 5 months and should return to normal within 3 months postpartum, otherwise it is not hyperemesis gravidarum but hypertension. Hyperemesis gravidarum is defined as gestational hypertension, i.e., high blood pressure with systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg that develops after 20 weeks (5 months) of gestation and returns to normal within 12 weeks postpartum, with negative urine protein. The disease is associated with impaired trophoblast recombination in the spiral arteries of the uterus during pregnancy and placental factors entering the mother, and therefore most often occurs after 20 weeks of gestation. Whereas hypertension that occurs before 20 weeks of gestation is mostly hypertension that was already present before pregnancy and is called chronic hypertension in pregnancy. Untreated hypertension in pregnancy may lead to damage to multiple organs and systems such as liver and kidney function, lungs, blood system, central nervous system, etc. Patients suspected of having this disease are advised to consult a doctor in time and follow the doctor’s instructions for further examination and treatment.