Overview, Causes, & Risk Factors
Hyperemesis gravidarum, also called HEG, is severe nausea and
vomiting during pregnancy. It results in dehydration, weight loss, and a
disturbance in the acid-base balance in the body.
Around half of all pregnant women have some nausea and/or
vomiting during the first few months of pregnancy. But HEG occurs in
less than 2 percent of all pregnancies (less than 5 in 1000 women).
What is going on in the body?
In most cases, nausea and vomiting during pregnancy is
mild and does not last long. When it becomes so severe that it interferes
with getting enough fluids and nutrients, the woman may need to
What are the causes and risks of the condition?
There is much that is not known about the causes and risks
related to HEG. Much more study is needed before experts will have
The exact cause of pregnancy-related nausea and vomiting remains
unclear. Some studies suggest the following:
There may be a link between high levels of estrogen or human
chorionic gonadotropin, a hormone that helps the unborn baby to develop.
There is a link between overactive thyroids, a lack of Vitamin B-6, also called
pyridoxine, and psychological factors.
A link between bacteria called Helicobacter pylori and HEG
No one race seems to be at risk for HEG, but it is less common
in the following races:
Asian natives, other than Japan
The risk for HEG seems to decrease as women grow older.
Cigarette smoking also seems to lower the risk. However, smoking presents other
risks to the unborn baby, so should not be used as a preventive factor!
Experts believe the following factors may increase the risk for
being pregnant for the first time
being pregnant with twins, triplets, or more
having HEG with a previous pregnancy
trophoblastic disease of the womb
Symptoms & Signs
What are the signs and symptoms of the condition?
Symptoms of HEG are at their peak at 8 to 12 weeks of pregnancy.
They usually resolve by the 16th week.
The main symptoms of HEG are severe and long-lasting nausea
and vomiting. Other common symptoms include:
ptyalism, which is excess production of saliva
fainting, also called syncope
HEG can also cause the following in some women:
loss of appetite
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extreme sensitivity to smells
impaired sense of taste
Diagnosis & Tests
How is the condition diagnosed?
Diagnosis is based on a history of the woman's symptoms
and a physical exam. Lab tests are also done to look for signs of
dehydration and electrolyte imbalances. These tests may include:
blood calcium level
serum electrolytes, which can show low
sodium levels in blood.
Low levels can mean dehydration or acid-base imbalance.
hematocrit, part of a blood count,
which may become high due to dehydration
liver enzymes and bilirubin
urinalysis for ketones and specific gravity. Ketones are a sign of starvation.
Specific gravity can show dehydration.
An ultrasound may also be done to check the condition of
the baby and the womb. If a woman has abdominal pain or vomits blood,
the doctor may do an endoscopy. This is a test where a small tube is
passed through a woman's mouth and throat down to her stomach. The
tube has a light at the end, which helps the doctor to look for problems
in the stomach.
Extreme nausea and vomiting in pregnancy may also mean
there are other more serious disorders going on. These include:
hydatidiform mole, which is an abnormal tumorous growth of the placenta
urinary tract infection
which is an inflammation of the gallbladder
Tests that may help to rule out other disorders include:
serum for hepatitis testing
liver function tests
ultrasound to look at gallbladder
to test for bacteria
ultrasound to look for twins or a tumorous growth of the placenta
Prevention & Expectations
What can be done to prevent the condition?
There is no known prevention for this condition.
What are the long-term effects of the condition?
Hyperemesis gravidarum usually goes away by the second
half of pregnancy. If treated, it should not present serious long-term problems
for most mothers or infants.
Treatment & Monitoring
What are the treatments for the condition?
The primary treatment for HEG should focus on diet and replacing
fluids, if the woman has become dehydrated.
Dietary changes that may help include:
eating frequent small meals rather than three large ones
eating when hungry, even if it is not mealtime
avoiding foods that do not appeal to the pregnant woman
avoiding foods high in fat and protein
staying away from spicy foods
eating more foods that have dry carbohydrates
drinking more carbonated drinks
drinking teas made from peppermint or ginger
eating soothing foods such as soup, soda crackers, unbuttered toast,
gelatin, or frozen desserts
avoiding milk products, which may be hard to digest
for some women
stopping prenatal vitamins and
until nausea and vomiting go away
drinking plenty of fluids to stay hydrated
In severe cases, a woman may need to enter the hospital for
IV fluids, vitamins, and electrolytes. Medicines such as antiemetics and sedatives
can also be used to calm the nausea. These include:
What are the side effects of the treatments?
The side effects depend upon which medicines are used to
What happens after treatment for the condition?
In most women, HEG clears up by the second trimester. If
a woman is not gaining enough weight, she may need to be given IV fluids
and nutrients again.