Hyperemesis gravidarum

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at August 25, 2016
StartDiseasesHyperemesis gravidarum

Approximately 70 percent of women experience nausea and vomiting during pregnancy. In most cases, these symptoms improve or go away around the 14th week of gestation. For women with an extreme form of morning sickness called hyperemesis gravidarum (sometimes referred to as HG), the symptoms do not resolve and can be so severe that they require hospitalization.


Definition & Facts

It is unclear exactly how many women suffer from hyperemesis gravidarum. However, it is believed to affect approximately one out of every 100 women. Those most at risk of developing HG include women who are overweight, who are carrying multiple babies, and first-time mothers. Women who experience hyperemesis gravidarum in one pregnancy are more likely to experience it in subsequent pregnancies.

HG is different from typical morning sickness in that the woman cannot keep any food or water down, and the extent and severity of the vomiting are such that she often becomes dehydrated.

While unpleasant, HG rarely causes harm to the baby as long as dehydration and other associated symptoms are properly treated; however, excessive weight loss during pregnancy may cause the baby to be born with a low birth weight. The dehydration caused by hyperemesis gravidarum can create a slightly increased risk of blood clots, especially if the woman remains in bed for extended periods of time.

Symptoms & Complaints

Symptoms of hyperemesis gravidarum usually start during the first trimester of pregnancy, but, unlike normal morning sickness, they do not resolve as the pregnancy progresses. Women with HG may vomit more than three or four times a day and experience near-constant nausea.

In extreme cases, women have reported vomiting up to 50 times a day. As a result, they may lose more than 10 pounds or five percent of their body weight. They may also experience symptoms of dehydration, including:

The stress of dealing with the physical symptoms and worrying about their effects on the unborn baby can also cause secondary symptoms of anxiety and depression.

Some women report that their HG symptoms improve after the 20th week of pregnancy; however, it is possible for them to continue until the baby is delivered. It is important that pregnant women experiencing the above symptoms seek medical attention since similar symptoms can also be caused by appendicitis and other health conditions.


It is unclear why some women develop hyperemesis gravidarum while others do not. Both morning sickness and HG appear to be connected to changing hormone levels during pregnancy. During pregnancy, the placenta produces a hormone called human chorionic gonadotropin, also known as hCG. The level of this hormone increases very rapidly during the first part of the pregnancy. According to the American Pregnancy Association, hCG levels can double every 48 to 72 hours. This sudden increase in hormones may play some role in causing HG symptoms.

There is also some evidence that genetic factors may also play a role in hyperemesis gravidarum. Women with a family history of the disease, that is, whose mothers or sisters suffered from HG, are more likely to experience it themselves.

A rare condition called gestational trophoblastic disease can also cause hyperemesis gravidarum. The condition occurs when abnormal cells grow in the uterus following conception and form a tumor.

Diagnosis & Tests

A medical history and physical examination may be enough to diagnose most cases of HG. A routine check of vital signs may reveal an abnormally low blood pressure and elevated pulse, which are signs of dehydration.

Blood tests and clinical urine tests may be used to check for dehydration, electrolyte imbalances, and other illnesses that may cause similar symptoms. Medical ultrasounds may be used to determine if the woman is pregnant with multiples or to identify the presence of a trophoblastic tumor.

Treatment & Therapy

As a general rule, the sooner a woman starts treatment for hyperemesis gravidarum the more effective the results and the lower the risk of serious dehydration. Medications, including promethazine, meclizine, and droperidol, may be used to control persistent nausea and vomiting. If the patient is unable to take oral medication, the drugs may be given through suppository or IV.

The woman may require hospitalization if medications are ineffective in controlling the vomiting. Hospital treatment typically includes administering IV fluids to restore and maintain hydration until the woman is able to tolerate fluids by mouth. In the most severe cases, the woman may require alternative forms of nutrition, such as nasogastric feeding, total parenteral nutrition through an IV, or a surgically implanted feeding tube.

A woman suffering from HG may also experience psychological and emotional symptoms related to the condition. They may feel emotionally isolated because they think no one else understands their symptoms. They may also become physically isolated since the constant sickness makes it difficult to leave the house and to carry on normal daily activities.

Women with HG may even be unsure about how to cope with the remainder of their pregnancy and motherhood. It is important that the woman is open and honest about her feelings and concerns when talking to her doctor or midwife so that they can recommend appropriate support resources.

Prevention & Prophylaxis

There is no way to prevent hyperemesis gravidarum; however, certain self-help measures may help lessen morning sickness and HG symptoms. This includes eating small frequent meals and avoiding greasy or spicy foods. It is also best to wait to take any iron supplements or prenatal vitamins until nausea symptoms have improved.

Many women who experience HG also find that they have an aversion to strong scents and that certain odors may trigger nausea symptoms, so it may be beneficial to avoid wearing scented bath products or perfumes and to avoid situations where there may be strong odors.

Some women find that a pressure-point wristband and certain supplements, such as ginger and vitamin B6, may help alleviate nausea; however, it is important to consult a doctor before taking any over-the-counter medicines or supplements.