I suspect that I had this! What is it? According to "What to Expect when you are Expecting- 3rd Ed", HG is an exaggerated from of morning sickness, characterized by excessive vomitting, which probably occurs in fewer than 1 in 200 pregnancies. It is more common in first-tim mums, young mums, obese women, multiple carrying mums.
I seem to have all the signs and symptoms for it.
1) Nausea and vomiting of early pregnancy is unusually frequent and severe (it may be almost impossible to keep anything down)
2) Infrequent urination and urine that is dark yellow (signs of dehydration from loss of fluids thru vomiting) *my urine looked like orange juice... seriously!
3) Weight loss of greater than 5% or original body weight *mine is 10%
4) Blood in the vomited material *yeck!
Fortunately my practitioner did not ask me to grin and bear it....like my sister's doctor. I was prescribed medication that helped quell the nausea so that I did not vomit as much. The doctor also told me to quit eating all vitamins as the iron in them made it worse. I was advised to eat only things that I could stomach... which in my case was all the horribly unhealthy food which I never like eating like potato chips, bread, porridge and biscuits... blek! But somehow my body accepted it more than fruits or vegetables.