Hyperemesis Gravidarum

More than 50 percent of pregnant women experience morning sickness in the early stages of pregnancy, but only 2 percent experience the condition known as hyperemesis gravidarum, which is characterized by debilitating nausea and vomiting that threatens the health of mother and baby alike. Hyperemesis gravidarum causes an estimated 50,000 women to be hospitalized each year—including, in 2012, England’s Duchess Catherine of Cambridge (née Kate Middleton).


The signature symptoms of hyperemesis gravidarum are constant nausea and excessive vomiting—three or four times a day—and an inability to keep food down for 24 consecutive hours, leading to weight loss. This becomes a matter of serious medical concern if the patient loses five pounds or more in a two-week period, or loses a total of more than 10 pounds. Other symptoms include:

  • Lightheadedness
  • Fainting
  • Pale complexion
  • Jaundice

Causes and Risk Factors for Hyperemesis Gravidarum

The exact cause of hyperemesis gravidarum is not known, but it is believed to be connected with the elevated levels of the hCG hormone that accompany pregnancy. Elevated levels of estrogen may also be a factor since that hormone affects the part of the brain that controls the vomiting reflex.

Other suspected causes of hyperemesis gravidarum include:

  • Gastrointestinal changes: As the uterus grows to make room for the baby, it pushes some of the other internal organs aside, which can cause acid reflux and other forms of stomach distress. Another consequence of this internal crowding is that the contents of the stomach may empty more slowly during the digestive process, which can also contribute to nausea during pregnancy.
  • Stress is a frequent cause of nausea even in people who are not pregnant, and pregnancy can bring about a great deal of emotional stress.
  • A high-fat diet: A woman’s risk for hyperemesis gravidarum increases fivefold with every 15 grams of saturated fat she consumes daily (this is roughly the amount of saturated fat found in a quarter-pound cheeseburger).
  • Bacteria: A recent study found that 90 percent of women who suffer from hyperemesis gravidarum are infected with a bacterium known as helicobacter pylori, which is also known to cause stomach ulcers.

Risk factors associated with hyperemesis gravidarum include:

  • Twins or multiples (possibly because a woman carrying more than one fetus produces more hCG)
  • First pregnancy
  • Mother under the age of 24
  • Expecting a girl: for some reason, hyperemesis gravidarum is more common in mothers carrying girls.
  • Obesity

Complications and Progression

Hyperemesis gravidarum commonly begins to appear in the first trimester, usually starting around the sixth week of pregnancy. In some cases it may resolve itself by around week 21.

If you are diagnosed with hyperemesis gravidarum, your doctor’s primary concerns are going to be dehydration and malnutrition. Nutrition, of course, is of the utmost importance for your baby’s health and development. Another cause for concern is the possibility that your excessive pregnancy vomiting may be an indication of a molar pregnancy.

Diagnosing Hyperemesis Gravidarum

As noted above, hyperemesis gravidarum strikes only about 2 percent of pregnant women, although some experts believe the condition may be underreported and underdiagnosed.

If you experience excessive nausea and vomiting during pregnancy, it is important that you do not ignore the problem. Make an appointment with your ob-gyn as soon as possible. Your doctor will want to conduct tests to rule out other conditions, such as molar pregnancy, stomach or intestinal problems, neurological disorders, thyroid conditions, liver problems, or—especially if it is late in your pregnancy—HELLP syndrome.

While examining you, your doctor will also attempt to measure the amount of weight you have lost and check to see whether you have abnormally low blood pressure or an abnormally high pulse rate. He or she will also likely want to test your urine for the presence of ketones; these are substances made when your body burns fat for energy, and they can be a sign of dehydration.


Mild cases of hyperemesis gravidarum can sometimes be ridden out with minimal medical intervention, even if this may be unpleasant for the mother to endure. If you are battling this condition, you may be able to manage it by eating more protein and carbs—e.g., nuts, crackers, milk, and dairy products such as cheese—and less fat.

Eating smaller portions may also be helpful, even if it means you need to eat more often. Drink plenty of fluids, especially seltzer or mineral water, and perhaps a little ginger ale now and then. Small doses of vitamin B6 may help, but take no more than 100 mg per day.

More severe cases of hyperemesis gravidarum will need to be treated with anti-nausea medications such as Unisom (doxylamine), Phenergan, Zofran Promethazine, or Meclizine. In severe cases, if other medications are not effective, methylprednisolone (Medrol) can be used after 10 weeks.

The most severe cases require a treatment regimen known as total parenteral nutrition (TPN). This means providing for all your nutritional needs—and the baby’s—via an IV tube, possibly for the remainder of your pregnancy.

While there is (as of this writing) no cure for hyperemesis gravidarum, scientists at the University at Buffalo have recently had some success in the testing of a drug known as gabapentin, which shows some promise. Currently it is prescribed as an anti-convulsant, but research has shown that gabapentin may have other applications.


While hyperemesis gravidarum is an unpleasant experience for the woman who suffers from it, the good news is that it is treatable, and if medical attention is sought early in the pregnancy the outcome will most likely be a normal—if difficult—pregnancy ending in the birth of a perfectly healthy baby.

This page was last updated on 06/2017

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