Hyperemesis Gravidarum: Everything to Know

Medically Reviewed By Stacy A. Henigsman, DO
Was this helpful?

Hyperemesis gravidarum is a type of sickness during pregnancy. It is characterizable by severe nausea and vomiting that persists until around the 20th week of pregnancy. Hyperemesis gravidarum can occur rapidly over a few weeks, or it can happen more gradually over a period of months. It can be a serious condition that may result in hospitalization.

Read on to learn more about hyperemesis gravidarum, including symptoms, possible causes, and treatments.

Is hyperemesis gravidarum the same as morning sickness?

A pregnant person is holding their stomach.
Ani Dimi/Stocksy United

Sickness during pregnancy, often called morning sickness, is common. It affects around 8 in 10 pregnant people.

Hyperemesis gravidarum may seem like severe morning sickness. However, the two conditions are not the same. Hyperemesis gravidarum is characterizable by severe and persistent sickness that can result in hospitalization.

You may be unsure whether you are experiencing morning sickness or hyperemesis gravidarum. The following attributes can help you distinguish between the two.

Attributes of morning sickness include:

  • nausea with possible vomiting
  • symptoms that last until around the 12th week of pregnancy
  • vomiting that does not result in dehydration
  • an ability to keep some food down

Attributes of hyperemesis gravidarum include:

  • nausea with severe vomiting
  • symptoms that last until around the 20th week of pregnancy
  • vomiting that can result in severe dehydration
  • an inability to keep any food down

Contact your doctor if you experience persistent nausea and vomiting during pregnancy. You may be experiencing hyperemesis gravidarum.

Learn more about morning sickness here.

What are the symptoms of hyperemesis gravidarum?

The main symptoms of hyperemesis gravidarum are severe and persistent nausea and vomiting. These can last until around the 20th week of pregnancy.

Other symptoms you may experience with hyperemesis gravidarum include:

  • an increasing pulse rate
  • ptyalism, or excessive salivation
  • tachycardia, or a rapid heartbeat
  • kenotic odor, or a distinct breath odor

Contact your doctor if you experience severe sickness during pregnancy. You may find that these symptoms subside and then recur.

What are the side effects of hyperemesis gravidarum?

Severe and persistent sickness can result in related side effects that may require hospitalization.

Possible side effects of hyperemesis gravidarum include:

Contact your doctor if you are experiencing any of these side effects.

What causes hyperemesis gravidarum?

Research into hyperemesis gravidarum is ongoing, as it is not always clear what causes the condition.

Hormones are the most widely studied possible cause of hyperemesis gravidarum. It is possible that human chorionic gonadotropin (hCG), thyroid, and steroid hormones contribute to the condition, as these often elevate at the beginning of pregnancy.

A 2022 study also links the placenta and appetite hormone gene GDF15 to hyperemesis gravidarum. It suggests that GDF15 is the greatest genetic risk factor for the condition.

Other possible causes of hyperemesis gravidarum include:

  • Gastric dysfunctions: Symptoms may reduce with gastric pacing, meals that reduce acid, metoclopramide prescriptions, and meals that are high in protein.
  • Nutritional deficiencies: It is possible that nutritional deficiencies worsen the symptoms of hyperemesis gravidarum. Thiamine depletion, which occurs with around 2 weeks of inadequate intake or from a high carbohydrate diet, can result in severe nausea and vomiting.
  • Thyroxine levels: Around 73% of hyperemesis gravidarum cases exhibit increased serum thyroxine levels. Your hCG levels can affect the hormone, which may result in short-term hyperthyroidism. It is possible that an overactive thyroid can influence the severity of hyperemesis gravidarum.

Experts continue to research causes of hyperemesis gravidarum, though there is a lack of funding and priority.

How do doctors treat hyperemesis gravidarum?

Treatments for hyperemesis gravidarum can include:

  • nutritional therapy
  • IV fluids, which doctors administer through a vein
  • prescribed medications

The type of treatment you receive will depend on how hyperemesis gravidarum affects you and how well you respond to the types of treatments available.

Nutritional therapy

Persistent sickness can cause vitamins and nutrients to quickly deplete. If hyperemesis gravidarum causes you to become malnourished, you may need nutritional therapy.

This may require you to spend time in the hospital to receive nutrients intravenously or through a tube.

If you require nutrients through a tube, this can be nasogastric tubing, wherein a tube passes through your nose and into your stomach. Alternatively, you may have a percutaneous endoscopic gastrostomy. This is where a tube delivers nutrients to the stomach through the abdominal wall.

IV fluids

Fluids delivered intravenously can help restore hydration, electrolytes, vitamins, and nutrients.

Although you may require hospitalization initially, you may be able to receive IV fluids as part of home care further into your treatment or if your symptoms become less severe over time.

Prescribed medications

Medications for hyperemesis gravidarum can include:

  • antiemetic medications to reduce vomiting
  • serotonin antagonists, which reduce symptoms for around 80% of people
  • antireflux medications to reduce reflux and gastric irritation
  • prokinetic agents, which can reduce vomiting that occurs after eating or drinking
  • antihistamines for milder cases of nausea and vomiting
  • phenothiazines for mild to moderate nausea and vomiting
  • corticosteroids for symptoms that do not respond to other medications

It is important to take prescribed medications as outlined in your treatment plan. Contact your doctor or medical care team if you begin to experience any side effects when taking medications.

Adverse effects of bed rest

Although your symptoms may make you feel tired or lethargic, it is important to be aware that too much bed rest can have adverse effects.

Prolonged bed rest can result in reduced physical fitness, which may affect your strength when you give birth. Your doctor may recommend physical therapy or muscle-tightening exercises to help overcome this.

Contact your doctor for advice on how to balance necessary bed rest with periods of physical therapy. This is an effective way to ensure that you can manage your symptoms without worrying about the long-term effects of too much bed rest.

Will I need to go to the hospital for hyperemesis gravidarum?

Up to 2% of pregnant people experience hyperemesis gravidarum. Specifically, a study of 8,215,538 pregnancies found that hyperemesis gravidarum affected around 1.48% of pregnant people.

Not everybody with hyperemesis gravidarum will need to go to the hospital. However, in the study, over half of the people with the condition did require hospitalization at some stage for monitoring, fluids, or nutrition therapy.

If your doctor thinks that you may benefit from hospitalization, they will discuss this with you and explain what it will entail before you need to make any decisions. In some cases, it is possible to receive IV fluids for dehydration at home.

How do doctors diagnose hyperemesis gravidarum?

It can be difficult to detect and diagnose hyperemesis gravidarum early, as some symptoms — such as weight loss — are not immediately noticeable.

Your doctor will first assess your symptoms alongside your pregnancy. Severe nausea and vomiting typically occur in the first trimester, and they can persist until around week 20. However, around 20% of people will continue to experience symptoms until late pregnancy or delivery.

Once they have ruled out other possible causes of nausea and vomiting, your doctor may arrange for blood tests to check for symptoms or side effects such as:

  • dehydration
  • electrolyte imbalances
  • deficiencies in vitamins D, K, and B1
  • increased liver enzymes
  • increased hematocrit, which indicates low blood volume

Following diagnosis, your doctor will be able to advise on the best course of treatment for you.

How common is hyperemesis gravidarum?

Nausea and vomiting, in general, affect up to 90% of pregnant people. This is compared with 0.5% to 2% of people who experience hyperemesis gravidarum.

Some people with hyperemesis gravidarum require hospital admission. In one study, 72% of people who required admission only needed to go to the hospital once. This is compared with 17% who required two admissions and 11% of people who required three or more admissions.

There has been an increase in hospitalization for the condition, with 1.03% of people requiring admission in 1998 increasing to 1.75% in 2011. This long-term study suggests increased awareness of the severity of the condition.

Is it possible to prevent hyperemesis gravidarum?

As it is not possible to determine the exact cause, you cannot prevent the onset of hyperemesis gravidarum.

However, you can take steps to reduce your symptoms or lessen their severity when they do occur. Steps can include:

  • Avoiding nausea triggers: Sensory stimuli that trigger nausea can differ for each person but include certain noises, lights, or smells. Once you identify the triggers for your nausea, try to avoid them where possible.
  • Staying hydrated: If you find it difficult to drink or keep fluids down, try sucking on ice cubes made from juice. You may also find it easier to drink through a straw or drink water that is colder.
  • Carrying food with you: Nausea can subside suddenly, and you may feel very hungry. This can be a good time to have something to eat, as it is important to get nutrients when you can.
  • Carrying a sick bag with you: Vomiting can happen with little warning, but carrying a sick bag with you can help. You may also choose to carry wipes, tissues, and a bottle of water with you.

Are there any complications of hyperemesis gravidarum?

Severe and persistent vomiting can result in numerous complications that may require hospitalization. These can include:

When should I contact a doctor?

Contact your doctor as soon as you notice symptoms of hyperemesis gravidarum.

The condition can be difficult to diagnose until symptoms such as dehydration and weight loss are more noticeable. However, your doctor will be able to assess your symptoms alongside your medical history to advise on how best to treat and monitor the condition.

Learn more

Visit our pregnancy hub for more articles.


Hyperemesis gravidarum is severe and persistent nausea and vomiting that occur during the first 20 weeks of pregnancy. It can be a serious condition that can require hospitalization for IV fluids and nutrition therapy.

Some medications can help with reducing nausea, vomiting, and related side effects. However, it is not usually possible to identify the cause of the condition.

Contact your doctor if you experience severe nausea and vomiting during your pregnancy. They can perform tests to check for side effects such as dehydration and vitamin deficiencies.

Was this helpful?
Medical Reviewer: Stacy A. Henigsman, DO
Last Review Date: 2022 May 12
View All Pregnancy Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.