Morning sickness

Approximately 50 percent of all pregnant women experience some degree of nausea and vomiting between the sixth and twelfth week of pregnancy. This is normal. Although it is commonly called morning sickness, it can occur at any time of the day. Abnormal vomiting – severe, continual nausea and vomiting after the twelfth week – occurs in approximately 1 in 300 pregnancies. This is called hyperemesis gravidarum, and it can result in dehydration, acidosis, malnutrition, and substantial weight loss. If the conditon persists, in can endanger the fetus. The reason for abnormally severe nausea is not clear, but an association has been made between it and very high levels of the hormone estrogen and chorionic gonadotropin (hCG), a hormone produced by the placenta that increases in quantity until the end of the first trimester. Other causes of abnormal vomiting include bile duct disease, drug toxicity, pancreatitis, low blood sugar, problems with the thyroid, and inflammatory bowel disorders.