Hyperemesis in early pregnancy. . Hyperemesis in early pregnancy. Vomiting is a normal feature of early pregnancy, especially between 7 and 12 weeks.Severe vomiting may cause weight loss and electrolyte imbalance. In very rare instances jaundice may result - thought to be due to severe protein and vitamin malnutrition.The cause of the vomiting is primarily physiological but psychological factors may affect the apparent severity .