Hyperemesis Gravidarum – Causes, Complications and Prevention

What is Hyperemesis Gravidarum?

Hyperemesis gravidarum is a severe and persistent form of morning sickness that occurs during pregnancy. While morning sickness is common in early pregnancy and often involves mild nausea and vomiting, hyperemesis gravidarum is characterized by excessive, unrelenting nausea and vomiting that can lead to dehydration, electrolyte imbalances, and weight loss. This condition typically begins in the first trimester and can last well into the second trimester or, in some cases, throughout the entire pregnancy. Hyperemesis gravidarum can significantly impact a woman’s ability to carry out her daily activities and may require hospitalization for intravenous fluids and medications to manage the symptoms.

The exact cause of hyperemesis gravidarum is not well understood, but hormonal changes in pregnancy, particularly the rapid increase in human chorionic gonadotropin (hCG) levels, are believed to play a role. Women with a history of motion sickness, migraines, or a family history of hyperemesis gravidarum may be at a higher risk. The condition can have serious implications for both the mother and the developing fetus, as severe dehydration and nutrient deficiencies can affect the overall health of both. Treatment often involves supportive measures such as intravenous fluids to prevent dehydration, anti-nausea medications, and dietary modifications. In some cases, hospitalization and nutritional support are necessary to ensure the well-being of both the mother and the baby.

Types of Hyperemesis Gravidarum

There are no specific types of hyperemesis gravidarum, but the severity of the condition can vary from mild to very severe.

  1. HG Severity Spectrum: HG does not have distinct types, but its severity varies among individuals.
  2. Mild HG: Some women experience milder symptoms, which can be managed with lifestyle changes, dietary modifications, and anti-nausea medications on an outpatient basis.
  3. Moderate HG: Moderate cases involve more frequent and intense vomiting, leading to weight loss and dehydration. These cases may require more intensive medical management, possibly including hospitalization for IV fluid therapy and antiemetic medications.
  4. Severe HG: Severe HG is characterized by relentless vomiting, significant weight loss, and severe dehydration. Women with severe HG often require hospitalization for aggressive IV fluid replacement, nutritional support, and close monitoring of electrolyte imbalances.


The criteria used to diagnose hyperemesis gravidarum (HG) often varies among health professionals and researchers. Patients who are very severe are typically hospitalized, representing the 1-3% of pregnancies estimated as having HG. However, very little research is done on the impact of hyperemesis as differentiated from morning sickness; thus, the impact of HG is likely greatly underestimated. One study by Zhang, et al found a 10.8% incidence of severe vomiting, and another study found 16% of pregnant patients using antiemetics. There are hundreds, if not thousands, of additional people who terminate out of desperation when given inadequate treatment despite debilitating symptoms. Hyperemesis (HG) is not really a rare disorder.

Pathophysiology of Hyperemesis Gravidarum

Its pathophysiology is complex and not entirely understood, but it is believed to involve a combination of hormonal, genetic, and environmental factors. One of the key hormones implicated in HG is human chorionic gonadotropin (hCG), which is produced by the placenta. Elevated levels of hCG, along with other pregnancy-related hormones like estrogen, are thought to trigger the severe nausea and vomiting experienced by women with HG. Genetic factors may also play a role, as some women may have a genetic predisposition that makes them more susceptible to the condition. Additionally, psychological factors such as stress can exacerbate symptoms, making the condition even more challenging to manage.

The persistent vomiting in HG can lead to dehydration, electrolyte imbalances, and nutritional deficiencies, posing significant risks to both the mother and the developing fetus. Dehydration can disrupt normal bodily functions and lead to electrolyte disturbances, which can have serious consequences for the heart, muscles, and nervous system. Nutritional deficiencies, especially in essential vitamins and minerals, can affect the overall health of the mother and the baby. Researchers continue to explore the intricate interplay of hormones, genetics, and environmental factors to gain a better understanding of HG’s underlying mechanisms. This knowledge is crucial for developing more effective treatments and interventions to alleviate the symptoms and improve the quality of life for women affected by this condition.

What are the symptoms of hyperemesis gravidarum?

Symptoms of hyperemesis gravidarum are similar to those of morning sickness, but they are more severe. They include:

  • Severe nausea and vomiting
  • Weight loss of 5% or more
  • Signs of dehydration such as dark urine, dry skin, weakness, light-headedness, or fainting
  • Vitamin and mineral deficiencies
  • Increased heart rate (tachycardia)
  • Increased salivation (ptyalism)
  • Constipation

The severity of this condition can result in a number of complications, including:

  • Depression and anxiety
  • Damage to the esophagus from vomiting and reflux
  • Delayed gastric emptying (gastroparesis)
  • Neurological changes like encephalopathy, vision changes, confusion, and delirium


Experts don’t know what causes HG or its milder form morning sickness but there are a few theories. Possibilities include:

  • Rising hormone levels, in particular the human chorionic gonadotropin (hCG) hormone released by the placenta
  • An increased sensitivity to smells
  • A slowed and more sensitive gastrointestinal tract
  • Genes involved in the development of the placenta

You’re more likely to have HG if you:

  • Tend to get motion sickness or migraines
  • Are pregnant with multiples
  • Had morning sickness or HG in a previous pregnancy
  • Have a mother or sister who had HG
  • Are pregnant with a girl
  • Suffer from an eating disorder

Risk factors

Risk factors can increase your chances of getting a condition such as this. They do not necessarily mean that you will always develop the condition due to that. Typical risk factors associated with Hyperemesis Gravidarum are as follows:

  1. Presence of the condition during an earlier pregnancy
  2. Being overweight
  3. Presence of multiple pregnancies
  4. Becoming a first-time mother
  5. Heartburn and acid reflux
  6. Migraine
  7. Hydatidiform mole or molar pregnancy
  8. Trophoblastic disease, which involves the growth of abnormal cells inside the uterus

Complications of Hyperemesis Gravidarum

With proper management, hyperemesis gravidarum is a temporary source of discomfort and stress.

However, without treatment, it can cause serious complications for both the pregnant woman and the developing fetus. These may include:

  • Wernicke’s encephalopathy, a dangerous neurological condition that can cause confusion, speech and communication issues, and other complications
  • Dehydration
  • Electrolyte imbalances
  • Severe malnourishment
  • Blood clots because of severe dehydration
  • Damage to the teeth because of excessive vomiting
  • Damage to the placenta
  • Low birth weight
  • Preterm labor
  • Congenital disabilities in the fetus

Rarely, severe untreated hyperemesis gravidarum can be fatal.


The diagnosis of hyperemesis gravidarum (HG) is typically made based on a thorough medical history, physical examination, and assessment of the patient’s symptoms. Healthcare providers use several criteria to diagnose HG and differentiate it from typical morning sickness:

Physical Examination

Physical examination is frequently unremarkable in women with probable hyperemesis gravidarum. The findings may be more useful if the patient has atypical symptoms suggestive of other illnesses, such as bleeding or abdominal pain.

Laboratory Tests

  • Blood tests. The doctor may ask to perform several blood tests to assess signs of dehydration.
  • Complete blood count. It will help identify and count all types of cells in the blood.
  • Serum electrolyte test. It will help measure the levels of all types of electrolytes in the blood.
  • It is a laboratory test of urine that will help detect signs of dehydration.
  • Ketones urine test. It will help identify whether the body has increased waste products or ketones.

Imaging Studies

The following imaging procedures may be used to evaluate women suffering from hyperemesis gravidarum:

  • Obstetric ultrasonography.This procedure is typically used to screen for multiple gestations, molar pregnancy, or trophoblastic illness.
  • Upper abdominal ultrasonography.This procedure assesses the pancreas and biliary tree when clinically required.
  • Abdominal CT scan or MRI.If appendicitis is suspected of causing nausea and vomiting during pregnancy, abdominal computed tomography scanning or magnetic resonance imaging should be performed.

How is hyperemesis gravidarum treated?

Treatment depends on your symptoms and how the condition is affecting your health. Up to 5% of women with the condition need to check in to a hospital.

Your doctor may first recommend:

  • Lifestyle changes. If you can eat, have smaller, more frequent meals. Drink smaller drinks, but drink more often, and through a straw. Try cold foods if hot one’s trigger nausea. Your doctor may want you to drink electrolyte-replacement sports drinks and nutritional supplements. Get enough sleep and try to manage your stress.
  • Ginger. Taking 1 to 1.5 grams a day in several small doses may help some women. You can get it in tea, lollipops, or supplements.
  • Pyridoxine. This vitamin, known as vitamin B6, is often prescribed for nausea in pregnancy. Typical doses are 10 mg to 25 mg, 3 times a day. Taking more may lead to temporary nerve damage.
  • Thiamine. This vitamin (also called vitamin B1) in doses of 1.5 milligrams a day may ease vomiting.
  • Medications. Your doctor can prescribe one or more drugs to help you throw up less. You can take them by mouth, suppository, IV, or in a shot. Antacids can also help. Another possible treatment is IV steroids. Your doctor will make sure any medications you take are safe for your baby.

If you’re still throwing up and dehydrated, your doctor may recommend you check in to the hospital. Once there you may get:

  • IV fluids. Doctors will give you saline and possibly electrolytes and vitamins to help keep you hydrated.
  • Tube feeding. If you can’t keep anything down, the doctor may give you nutrition through a tube that goes through your nose and into your stomach. In extreme cases you may need a tube connected directly to your stomach or small intestine.
  • IV feeding. This bypasses the stomach altogether.

Once you aren’t vomiting so much and are able to hold down food and remain hydrated, you may be able to stop treatments.

Try to remember that it does eventually stop and the birth of your baby will follow.

Alternative and Complementary Therapies

Evidence concerning the effectiveness of the following therapies for hyperemesis gravidarum remains inconclusive. But when used in addition to traditional medical interventions, they may help alleviate symptoms. They include:

  • Hypnosis
  • Light therapy (to help with depression)

Before trying either of the above, make sure to discuss their use with your healthcare provider.

Hyperemesis gravidarum diet

One of the best ways to manage hyperemesis gravidarum is by modifying your diet. It’s important to try to eat small, protein-rich meals throughout the day.

  • Eating now, drinking later.Eat in one sitting and then drink a little later, so you’re not loading up your stomach all at once.
  • Frequently eating. Have mini-meals or snacks throughout the day so your stomach isn’t empty, which can spark nausea.
  • Embracing light carbs. Crackers, bread and pretzels are your friends right now.

How to prevent hyperemesis gravidarum?

Hyperemesis gravidarum cannot always be entirely prevented, as its exact cause is not well understood and can vary from woman to woman.

However, there are some strategies that may help reduce the risk or manage symptoms:

  1. Early Prenatal Care: Early and regular prenatal care is essential. Inform your healthcare provider about your medical history, especially if you have a family history of HG, so they can monitor your condition closely.
  2. Hydration and Nutrition: Stay well-hydrated and maintain a balanced diet with small, frequent meals to prevent an empty stomach, which can trigger nausea. Avoid spicy, fatty, or strong-smelling foods that may worsen symptoms.
  3. Ginger: Some women find relief from nausea by consuming ginger in various forms, such as ginger tea or ginger candies. However, consult your healthcare provider before using ginger supplements, especially in high doses.
  4. Acupressure and Acupuncture: Some women find relief from nausea and vomiting through acupressure wristbands or acupuncture. Consult a qualified practitioner before trying these methods.
  5. Rest and Stress Reduction: Get plenty of rest and find ways to manage stress, as anxiety and fatigue can exacerbate symptoms. Relaxation techniques, prenatal yoga, or meditation might be helpful.
  6. Avoid Triggers: Identify and avoid triggers that worsen your symptoms, whether they are specific smells, foods, or environmental factors.
  7. Medications: If you are planning a pregnancy and have a history of severe HG in previous pregnancies, discuss preventive medications with your healthcare provider. Certain antiemetic medications taken before symptoms become severe may help manage nausea and vomiting.
  8. Consider Professional Help: If you had HG in a previous pregnancy, consider consulting a high-risk pregnancy specialist (perinatologist) before becoming pregnant again. They can provide personalized guidance and a proactive management plan.

It’s crucial to note that every woman’s experience with HG is different, and what works for one person may not work for another.

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One comment

  1. The reading about pregnancy sickness has been very interesting, and now I know that the gynecologist are available to help, thanks.

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