Hyperemesis Gravidarum

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 be treated.

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 definite answers.

Causes

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 may exist.

    • Risks

    No one race seems to be at risk for HEG, but it is less common in the following races:

  • American Indian
  • Eskimo
  • African natives
  • 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 HEG:

  • being pregnant for the first time
  • being pregnant with twins, triplets, or more
  • having HEG with a previous pregnancy
  • being overweight
  • 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
  • weight loss
  • fatigue
  • lightheadedness
  • fainting, also called syncope
  • weakness

    • HEG can also cause the following in some women:

  • loss of appetite
  • decreased concentration
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  • irritability
  • mood changes
  • trouble sleeping
  • 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:

  • amylase
  • blood calcium level
  • serum electrolytes, which can show low potassium or 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
  • viral gastroenteritis
  • flu
  • food poisoning
  • hepatitis A
  • hepatitis B
  • hepatitis C
  • urinary tract infection
  • appendicitis
  • cholecystitis, which is an inflammation of the gallbladder
  • ulcers

    • Tests that may help to rule out other disorders include:

  • serum for hepatitis testing
  • liver function tests
  • ultrasound to look at gallbladder
  • urinalysis and culture 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 iron 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:

  • promethazine
  • hydroxyzine
  • trimethobenzamide
  • prochlorperazine

    • What are the side effects of the treatments?

    The side effects depend upon which medicines are used to control nausea.

    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.

    Attribution

    Author:Eva Martin, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:10/22/02
    Reviewer:Kathleen A. MacNaughton, RN, BSN
    Date Reviewed:10/22/02