I dont think i have ever really posted about what hyperemisis is.... so here is a little bit of info taken from a great website www.helpher.org the leading website about HG for familys who are dealing with this during pregnacy.
"Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting in pregnancy. It is generally described as unrelenting, excessive pregnancy-related nausea and/or vomiting that prevents adequate intake of food and fluids. If severe and/or inadequately treated, it is typically associated with:
-loss of greater than 5% of pre-pregnancy body weight (usually over 10%)
-dehydration and production of ketones
-difficulty with daily activities
HG usually extends beyond the first trimester and may resolve by 21 weeks; however, it can last the entire pregnancy in less than half of these women. Complications of vomiting (e.g. gastric ulcers, esophageal bleeding, malnutrition, etc.) may also contribute to and worsen ongoing nausea."
more info can be found here: http://www.helpher.org/hyperemesis-gravidarum/