I had four children and varying levels of sickness. One I threw up for 3 straight months and lost 25 pounds, but my babies were all healthy.
My sister-in-law had the same condition as Kate. She couldn't keep anything down from the second month until the day she had the baby. She was hospitalized several times suffering from severe dehydration and nutritional deficiencies. That causes other problems. It was a pregnancy from hell and we are lucky she and the baby are now fine. Please don't minimize Kate's condition - it is a serious and dreadful way to go through a pregnancy.