Nearly eighty percent of all pregnant women experience morning sickness, so it is not surprising that many people mistakenly discount hyperemesis gravidarum. The degree of intensity is the most notable difference between morning sickness and hyperemesis gravidarum. With normal morning sickness, nausea is occasionally followed by vomiting, but not always. This vomiting does not cause dehydration and allows the woman to keep down some foods. It also goes away after the 12th week of pregnancy. With hyperemesis gravidarum, nausea is almost always followed by severe vomiting and does not go away after 12 weeks. It causes dehydration and makes it difficult to keep down any food at all.

bobbieo / Getty Images
This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.