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Hyperemesis gravidarum

Morning Sickness, Vomiting During Pregnancy

What is Hyperemesis gravidarum?

Hyperemesis gravidarum refers to vomiting during pregnancy that is so severe and persistent it causes weight loss, dehydration, nutritional deficiencies, electrolyte imbalance, pH imbalance (metabolic acidosis), and possible liver damage. Approximately two out of each 1,000 pregnant women have this condition so severely that they require hospitalization. If untreated, it can be fatal.

Hyperemesis gravidarum is believed to be related to the high hormonal levels in the blood due to the pregnancy, although the exact cause is unknown. Most women experience some nausea and vomiting during the first trimester of pregnancy, but hyperemesis gravidarum often persists for the duration of the pregnancy. A woman who vomits during pregnancy but continues to gain weight and is not dehydrated, does not have hyperemesis gravidarum.

Potential causes of morning sickness

Hyperemesis gravidarum signs and symptoms

  • Severe nausea.
  • Sustained vomiting (usually 4 to 8 weeks), first of mucus, then of bile and finally of blood.
  • Dehydration.
  • Failure to gain weight, or weight loss to less than prepregnancy weight.
  • Pale, waxy, dry and sometimes yellow skin.
  • Rapid heartbeat.
  • Headache, confusion or lethargy.

The exact cause of morning sickness is unknown. Many physicians believe that hormones play a role. During pregnancy there is a sudden increase in hormones. Rising levels of human chorionic gonadotropin (HCG), a hormone secreted by the fetus, is considered a factor. Rising levels of the female hormone estrogen levels have also been implicated. Some experts believe pregnancy hormones cause nausea and vomiting by relaxing the stomach.

The hormone theory is also supported by the fact that morning sickness usually disappears by the second trimester, the time the levels of pregnancy hormones fall. In addition to hormones, lower blood sugar during early pregnancy has been considered a potential cause of morning sickness.

Many researchers believe that hormones and morning sickness played an important role during human evolution. A common theory is that morning sickness during pregnancy protects the fetus by preventing the mother from eating foods that would be harmful to the pregnancy. This idea is supported by the fact that many of the foods that commonly repulse pregnant woman contain potentially harmful substances.

In addition, some studies have indicated that women who have little or no nausea or vomiting during pregnancy seem to be more likely to miscarry than those who experience some sickness. Many physicians believe morning sickness is a positive sign because it signals that the afterbirth (the placenta and fetal membranes) is developing properly. However, this link is not certain, and many women who experience little or no morning sickness have normal pregnancies.

In some women, an increased sensitivity to odor may also contribute to morning sickness. Pregnancy may cause the development of aversions to certain foods such as coffee or meat. The dislike for these foods is often associated with their odor. Many women experience an enhanced sense of smell during their pregnancy. This can result in these women becoming more sensitive to odors, triggering nausea and vomiting. Pregnant women may also experience changes in the taste of some foods.

How is it treated?

There are many methods pregnant women can use to relieve the nausea associated with morning sickness. Common methods include avoiding certain foods and fluids such as:

  • Greasy or fatty foods
  • Highly seasoned foods
  • Onions and other strongly flavored vegetables
  • Cream or heavy dairy products
  • Foods that smell unpleasant
  • Large amounts of coffee or tea
  • Coffee, tea, citrus juice and milk (with meals)
Women may be able to avoid morning sickness or reduce the symptoms by following a few changes:
  • Eat five or six small meals a day instead of three large meals. The stomach should never feel empty because nausea is more likely to occur on an empty stomach.
  • Eat more carbohydrates, such as a plain baked potato, white rice or dry toast.
  • Eat snacks that are high in protein, such as peanut butter, nuts, pasteurized cheese, cottage cheese and yogurt.
  • Eat bland foods when feeling nauseous, including saltine crackers, gelatin, broth and ginger ale.
  • Eat saltine crackers or dry bread before going to sleep at night and upon waking in the morning. A small snack should also be eaten when getting up to go to the bathroom in the middle of the night. Many women find it helpful to keep crackers by their bed to help prevent nausea in these situations.
  • Drink fluids often throughout the day. Drinking fluids is important to prevent dehydration. To avoid nausea, drink liquids between meals instead of during meals. Try broth, caffeine-free soft drinks, sports drinks, fruit juice, seltzer or other types of sparkling water. If liquids upset the stomach, try eating crushed ice or popsicles. Most women become aware of which drinks are better tolerated.
Other helpful tips include:
  • Get plenty of rest and take breaks when periods of low energy arise.
  • Get up slowly in the morning. Sit on the side of the bed for a few minutes before standing up. Eat a cracker or sip a drink before getting up.
  • Suck on a piece of hard candy.
  • Wear an acupuncture wristband. Commonly worn by boat and airline passengers to prevent motion sickness, these wristbands may help alleviate morning sickness. They work by placing pressure on an accupressure point on the inside wrist. They are available at drug stores, health food stores, boating stores and travel agencies. Although they do not work for everyone, many women report relief with these bands.
  • Take prenatal vitamins at night. The iron in prenatal vitamins can cause nausea in some women. Taking the vitamins at night or on a full stomach may help prevent morning sickness. If the nausea persists, discuss the vitamins with a physician. The physician may choose to change the vitamins.
  • Increase the amount of vitamin B-6. Sources of vitamin B-6 include whole grains, nuts, seeds and legumes. A physician may also suggest vitamin B-6 supplements.
  • Consume ginger. The spice can be found in ginger soda, ginger tea and gingersnaps. It is also available in capsules and a crystallized form that can be sucked or chewed. Ginger has been shown to relieve nausea and other symptoms of motion sickness.
  • Avoid strong or unpleasant smells.
  • Keep rooms well-ventilated to reduce odors. Also, cool temperatures may be better for some women.
  • Avoid smoking and second-hand smoke.
  • Keep a record of what elements may have contributed to the morning sickness. By avoiding the items, such as certain foods or drinks, women may reduce the chance of sickness.
Although there are medications available to treat morning sickness, women should always discuss these options with their obstetrician-gynecologist (ObGyn) before taking them. Women should also discuss nutritional or herbal supplements, such as ginger capsules and B-6 supplements, with their physician before using them. Women who are considering alternative treatments, such as acupuncture, should discuss these options with their physician as well. It is also important only to use individuals involved in complementary and alternative medicines who are trained to work with pregnant women.

Unlike typical morning sickness, hyperemesis gravidarum (a disorder characterized by frequent and severe vomiting) may require medical treatment. When vomiting is frequent, and severe enough to pose a threat to the expectant mother or her fetus, medication may be prescribed to reduce nausea and vomiting. In severe cases, the mother may require hospitalization and intravenous (I.V.) fluid administration to balance the level of electrolytes in the blood. Treatment may also require fasting, followed by a slow introduction of food back into the diet.



Don't use any medicine, including non-prescription medicine to prevent vomiting, without medical advice.

  • Intravenous fluid and electrolyte replacement if your condition is serious. Intravenous vitamin therapy and antinausea drugs may be required.
  • If other drugs are prescribed for you, carefully follow instructions on the label.

Phenergan (Promethazine)


  • Bed rest may benefit some patients.
  • After recovery, resume activities slowly and as your strength allows. Work and exercise moderately. Rest often.


If the condition has not reached the point to warrant hospitalization for intravenous fluids, follow these instructions:

  • If you feel nauseated in the morning, eat dry toast or saltine crackers before you get out of bed.
  • Eat small, frequent meals.
  • Don't eat fried or spicy foods; they increase nausea. Limit dairy products, especially butter, milk and cheese.
  • Sit upright for 45 minutes after eating.
  • If intravenous fluids are necessary, you will probably progress from them to a clear liquid diet, full liquid diet and then regular diet with small, frequent meals.

Predicted outcome

Predicted outcome is excellent. The condition is generally self-limiting, but death and serious complications are possible. With increasing sophistication of home care modalities, there is little reason for long-term hospitalization.


Conditions with similar symptoms include peptic ulcer, pyelonephritis, pancreatitis, cholelithiasis, cholecystitis, hepatitis, appendicitis, and hydatidiform mole.

Appropriate specialists

Obstetrician or gynecologist.

Seek Medical Attention

  • You or a family member has symptoms of hyperemesis gravidarum.
  • Nausea, vomiting or weight loss worsen, despite treatment.

Last updated 17 July 2015