HG in pregnancy stands for Hyperemesis Gravidarum, which is a condition that causes extreme, persistent nausea and vomiting during pregnancy. It is sometimes called severe morning sickness, but it is much more severe than typical morning sickness. The exact cause of HG is not known, but it is believed to be caused by a rapidly rising blood level of a hormone called human chorionic gonadotropin (HCG), which is released by the placenta. Symptoms of HG usually appear between 4-6 weeks of pregnancy and may peak between 9-13 weeks. Most women receive some relief between weeks 14-20, although up to 20% of women may require care for hyperemesis throughout the rest of their pregnancy. HG can lead to weight loss, dehydration, and electrolyte imbalances. It is uncommon and affects less than 3% of pregnant people. If left untreated, HG can affect the health of both the mother and the fetus. Treatment for HG may include avoiding foods that trigger the problem, drinking plenty of fluids, and taking medications to prevent nausea. In severe cases, hospitalization may be necessary for intravenous antiemetics and fluids.