Many pregnant
women experience morning sickness, usually during their first trimester. In
fact, 70%-80% of pregnant women report having some degree of morning sickness,
according to the American Pregnancy Association. While pesky, this condition is
quite normal and (blessedly) short in duration.

However, in about 1% of pregnancies,
women will experience a much more severe form of morning sickness called hyperemesis
gravidarum,
says the American Pregnancy Association. Although the condition is thought to
be caused by a rise in hormone levels, the cause is still unknown.

Hyperemesis gravidarum is
characterized by severe nausea, vomiting, weight loss and electrolyte
disturbances. Although mild cases react well to dietary change, rest and
antacids, severe cases often require a hospital stay to allow treatment with
intravenous fluids and nutrients.

So how can pregnant women
differentiate between morning sickness and hyperemesis gravidarum? Here are
some distinctions between the two conditions:

Morning Sickness Hyperemesis Gravidarum
nausea (sometimes with vomiting) nausea with severe vomiting
nausea ends at 12 weeks or sooner nausea does not subside
vomiting without severe dehydration vomiting that causes severe dehydration
vomiting but can keep some food down vomiting; unable to keep any food down

Source: The American Pregnancy Association 2007.