Hyperemesis Gravidarum

ByAntonette T. Dulay, MD, Main Line Health System
Reviewed/Revised Apr 2024
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Hyperemesis gravidarum is extremely severe nausea and excessive vomiting during pregnancy.

  • Women with hyperemesis gravidarum, unlike women with ordinary morning sickness, lose weight and become dehydrated.

  • Doctors diagnosis hyperemesis gravidarum based on symptoms and do tests to check for dehydration and other possible causes of the vomiting.

  • Treatment involves nothing by mouth at first, fluids containing electrolytes and vitamins given by vein, and medications to relieve the nausea, and rarely, giving all food intravenously.

(See also Nausea and Vomiting During Early Pregnancy.)

Pregnancy frequently causes nausea and vomiting. It usually occurs in the morning (as so-called morning sickness), although it can occur any time of day. This type of nausea and vomiting usually starts around 5 weeks of pregnancy and is at its worst at about 9 weeks. It disappears by about 16 to 18 weeks.

Hyperemesis gravidarum differs from typical morning sickness. If women vomit often and have nausea to such an extent that they lose weight and become dehydrated, they have hyperemesis gravidarum. If women vomit occasionally but gain weight and are not dehydrated, they do not have hyperemesis gravidarum.

The cause of hyperemesis gravidarum is unknown.

Symptoms of Hyperemesis Gravidarum

Women with hyperemesis gravidarum may not consume enough food to provide their body with energy. Then the body breaks down fats, resulting in a buildup of waste products (ketones) called ketosis. Ketosis can cause fatigue, bad breath, dizziness, and other symptoms.

Women with hyperemesis gravidarum often become so dehydrated that the balance of electrolytes, needed to keep the body functioning normally, is upset. Dehydration can also cause other problems such as a rapid heart rate, low blood pressure, and, rarely, abnormal heart rhythms.

Hyperemesis gravidarum may cause the thyroid gland to become slightly and temporarily overactive (called hyperthyroidism).

Rarely, hyperemesis gravidarum continues after 16 to 18 weeks of pregnancy. If it does, the following may occur:

  • The liver may be severely damaged, causing jaundice and break down of liver tissue. If damage to the liver or dehydration is severe, women can become confused.

  • Wernicke encephalopathy may develop, It may cause confusion, drowsiness, eye problems, and loss of balance.

  • The esophagus may rupture.

Diagnosis of Hyperemesis Gravidarum

  • Sometimes regular measurements of weight

  • Blood and urine tests

Doctors ask women about the vomiting:

  • When it started

  • How long it lasts

  • How many times a day it occurs

  • Whether anything relieves or makes it worse

  • What the vomit looks like

  • How much vomit there is

Doctors suspect hyperemesis gravidarum based on symptoms. Regularly measuring the woman's weight can help support the diagnosis of hyperemesis gravidarum. If doctors suspect this disorder, they do blood and urine tests to determine whether dehydration is present and to check for electrolyte abnormalities, which may result from dehydration.

Ultrasonography is usually done to determine whether women have a hydatidiform mole (a disorder that initially resembles pregnancy) or more than one fetus (multiple births). Either condition may make vomiting more likely.

Other tests may be done to rule out other possible causes of vomiting.

Treatment of Hyperemesis Gravidarum

  • Nothing by mouth at first

  • Fluids given intravenously

  • Medications to relieve nausea

  • Rarely, intravenous feeding

If hyperemesis gravidarum is confirmed, the woman is given nothing by mouth at first. Instead, she is given fluids intravenously. The fluids usually contain sugar (glucose) and include electrolytes and vitamins as needed. If vomiting is severe and persists, the woman is hospitalized and continues to be given fluids containing any needed supplements. She is also given medications to relieve nausea (antiemetics) by mouth, injection, or suppository.

After a woman is rehydrated and vomiting has subsided, she is given fluids to drink. If she can tolerate fluids, she can begin eating frequent, small portions of bland foods. The size of the portions is increased as she can tolerate more food. If she cannot drink fluids, she may need to be given fluids intravenously in the hospital or at home for a longer period of time.

If symptoms recur, the treatment is repeated.

If vomiting continues despite treatment and causes continuing weight loss, jaundice, and abnormal heart rhythms in the mother, the mother's life may be in danger. In such cases, ending the pregnancy may be an option. Women can discuss this option with their doctor.

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