Hyperemesis gravidarum

Hyperemesis gravidarum, often shortened to HG, is severe nausea and vomiting during pregnancy. It is more serious than the common nausea sometimes called “morning sickness.”

HG can make it difficult or impossible to eat, drink, work, sleep, or manage everyday tasks. Vomiting may happen many times a day, but some people have severe, constant nausea with less frequent vomiting. Symptoms can lead to dehydration, weight loss, and changes in the body’s salts, called electrolytes.

The condition usually begins early in pregnancy. It may improve as pregnancy progresses, but it can last beyond the middle of pregnancy or, for some people, until birth.

HG is a physical pregnancy condition. It is not caused by a lack of willpower, anxiety, or being unhappy about the pregnancy. However, prolonged symptoms can affect mood, relationships, finances, and quality of life.

Treatment can reduce nausea, replace lost fluids, and support nutrition. Some people can be treated at home, while others need treatment in a clinic or hospital.

HG affects people differently. The severity may also change from one day to the next.

Symptoms can include:

• Severe or persistent nausea
• Repeated vomiting or retching
• Difficulty keeping down food, drinks, or medicines
• Weight loss or little expected pregnancy weight gain
• Passing less urine or having dark urine
• Dizziness, weakness, or feeling faint
• Excess saliva and frequent spitting
• Strong sensitivity to smells, movement, light, or sound
• Headaches, constipation, or abdominal soreness from vomiting
• Trouble completing normal daily activities

Morning sickness can occur at any time of day. HG may also be constant rather than limited to mornings.

Blood in vomit is not a usual symptom. Small streaks can sometimes follow forceful vomiting because of irritation or a small tear in the food pipe. More than a small streak, repeated bleeding, or dark vomit that resembles coffee grounds needs urgent assessment.

Fever, severe abdominal pain, painful urination, diarrhea, or symptoms starting later in pregnancy may point to another condition and should be assessed.

The exact cause of HG is not fully understood. Research suggests that signals between the placenta, fetus, and pregnant person play an important part.

One hormone linked to HG is GDF15. This hormone is produced in high amounts by the placenta during pregnancy and acts on an area of the brain involved in nausea and appetite. A person’s sensitivity to GDF15 may help explain why symptoms are mild in some pregnancies and severe in others.

Genetic factors are also involved. HG can run in families, and having had it in an earlier pregnancy raises the chance of experiencing it again.

Other factors associated with a higher chance of severe pregnancy sickness include:

• A multiple pregnancy, such as twins
• A molar pregnancy, in which abnormal placental tissue grows
• A previous pregnancy affected by HG
• A history of severe nausea with estrogen-containing medicines
• Certain medical conditions, including migraine

These factors do not mean that HG will definitely occur. It can also develop without any known risk factor.

Stress does not cause HG. Severe illness may cause understandable worry, low mood, or trauma, but these are effects that may need support rather than explanations for the vomiting.

There is no single blood test, scan, or urine test that confirms HG. Diagnosis is based on your symptoms, how much they limit eating and drinking, and their effect on daily life. Other possible causes of vomiting must also be considered.

A healthcare professional may ask when symptoms began, how often you vomit, what you can keep down, whether you are passing urine, and whether you have lost weight. They may check your pulse, blood pressure, temperature, weight, and signs of dehydration.

Blood tests can look for changes in electrolytes, kidney function, liver function, blood count, and sometimes thyroid function. Urine may be checked for infection and other abnormalities. Ketones in urine can occur when the body is using fat for energy, but ketone levels alone do not show how severe HG is.

An ultrasound may be offered to confirm the stage of pregnancy and check for twins or a molar pregnancy. It is not a test for HG itself.

Further testing may be needed if symptoms are unusual, begin later in pregnancy, or occur with pain, fever, neurological symptoms, or urinary problems.

Treatment aims to control nausea and vomiting, correct dehydration, protect nutrition, and help you function as normally as possible. The approach depends on what you can keep down and whether tests show complications.

Anti-sickness medicines, also called antiemetics, are a central part of treatment. Several types are used during pregnancy. They work in different ways, so a combination may be considered when one medicine is not enough. Medicines may be given as tablets, dissolvable forms, suppositories, injections, or through a vein if swallowing is difficult.

Some people worry about taking medicine during pregnancy. Untreated HG also has risks, and established anti-sickness treatments have pregnancy safety information. A healthcare professional can discuss the known benefits and uncertainties of each option.

Fluids containing salts may be given through a vein if you cannot drink enough. Blood tests guide the replacement of electrolytes such as potassium. Thiamine, a form of vitamin B1, is important for people with prolonged vomiting, especially before receiving fluids containing glucose.

Other treatment may include:

• Medicine for acid reflux or irritation of the stomach and food pipe
• Treatment for constipation caused by dehydration or medicines
• Nutrition drinks or advice from a dietitian
• Temporary hospital or day-unit care for fluids and monitoring
• Measures to reduce blood-clot risk during some hospital admissions
• Corticosteroid treatment for severe symptoms that have not responded to usual options

A small number of people need feeding through a tube into the digestive tract. Feeding through a vein may be considered in exceptional circumstances when other nutritional support is not possible. These treatments require specialist monitoring.

Small, frequent amounts of any tolerated food or fluid may be easier than full meals. There is no single HG diet. Cold foods, bland foods, ice, or sipping through a straw help some people but make no difference to others. Avoiding a trigger is reasonable when possible, but you are not responsible for controlling symptoms through diet alone.

Most complications can be treated or reduced with timely medical care. Possible problems include dehydration, electrolyte disturbances, malnutrition, and loss of muscle strength.

Prolonged vitamin B1 deficiency can cause Wernicke encephalopathy, a rare but serious brain condition. Warning signs include confusion, difficulty walking, unusual eye movements, or vision changes. This needs emergency treatment.

Repeated forceful vomiting can inflame or tear the food pipe and may cause bleeding. Severe dehydration can affect kidney function. Reduced movement, dehydration, and pregnancy can also increase the risk of a blood clot.

When severe symptoms and poor weight gain continue, there may be an increased chance of the baby being born early or smaller than expected. Pregnancy care may include monitoring growth if symptoms persist.

HG can also contribute to depression, anxiety, social isolation, and trauma symptoms. Thoughts of self-harm or feeling unable to stay safe require immediate support.

There is no guaranteed way to prevent HG. It is not caused by something you ate, did, or failed to do.

If you have had HG before, planning before or early in another pregnancy may help reduce its impact. This can include discussing which medicines helped previously, arranging early access to care, and making practical plans for childcare, work, meals, and transport.

Starting treatment when symptoms first appear may prevent dehydration and weight loss from becoming more severe. This does not mean that worsening symptoms are your fault or that every hospital visit can be prevented.

HG often starts in the early weeks of pregnancy. Many people improve by the middle of pregnancy, but symptoms can continue for longer. A smaller group remains unwell until birth. It is not possible to predict an individual course from early symptoms alone.

Treatment needs may change over time. A medicine that works for a while may become less effective, or you may need different ways of taking it. Routine follow-up may include reviewing food and fluid intake, weight, blood results, medicines, mental health, and the baby’s growth.

Daily life may become very limited. Smells from cooking, travel, screens, showers, or movement can trigger symptoms. Accepting practical help and reducing non-essential tasks can protect energy. Emotional support is also part of care, not a sign that symptoms are psychological.

Symptoms usually settle after the pregnancy ends, although recovery from weight loss, weakness, sleep disruption, and emotional distress may take longer. New or continuing vomiting after birth should be assessed rather than assumed to be HG.

HG often returns in later pregnancies, but the severity is not always the same. A record of medicines, fluids, and other measures that helped can support planning for the future.

Contact your pregnancy care team promptly if vomiting is getting worse, you are losing weight, or you cannot keep down enough food, fluid, or prescribed medicine. Passing much less urine, having dark urine, or feeling dizzy when standing can indicate dehydration.

Seek urgent same-day care if you:

• Cannot keep fluids down
• Have not passed urine for many hours
• Feel very weak, drowsy, or close to fainting
• Have abdominal pain, fever, or painful urination
• See blood in your vomit
• Develop a painful, swollen leg

Call emergency services or go to an emergency department if you faint, become confused, have difficulty walking, vomit a significant amount of blood, have severe chest pain, or develop sudden shortness of breath. These are not routine HG symptoms.

Get immediate help if you have thoughts of harming yourself or do not feel able to stay safe.

Routine follow-up is appropriate when symptoms are stable and you can keep down enough fluid and medicine. You should still report ongoing weight loss, medicine side effects, worsening mood, or a change in your usual symptoms.

Is hyperemesis gravidarum just severe morning sickness?

HG is at the severe end of pregnancy-related nausea and vomiting, but the term describes more than frequent sickness. It can prevent normal eating and drinking, disrupt daily activities, and cause dehydration, weight loss, or nutritional problems.

Will hyperemesis gravidarum harm my baby?

Most pregnancies affected by HG do not result in serious problems for the baby, especially when dehydration and nutrition are managed. Persistent severe symptoms and low pregnancy weight gain can be associated with earlier birth or lower birth weight, so additional monitoring may be offered.

How long does hyperemesis gravidarum last?

Many people improve during the second trimester, which begins around week 13. Others remain unwell beyond 20 weeks or until birth. Symptoms usually resolve after the pregnancy ends, but physical and emotional recovery can take additional time.

Can I take anti-sickness medicine while pregnant?

Several anti-sickness medicines are used in pregnancy and have established safety information. The most suitable choice depends on symptom severity, medical history, side effects, and what you can keep down. More than one type may be needed.

Why do I still feel sick if I am not vomiting?

Severe nausea alone can prevent eating, drinking, sleeping, and functioning. The number of times you vomit does not fully measure the impact of HG. Tell your care team what you can consume and how symptoms affect daily life.

Will I get hyperemesis gravidarum in my next pregnancy?

A previous HG pregnancy increases the chance of recurrence, but it cannot predict exactly how severe another pregnancy will be. Pre-pregnancy planning and early access to treatment may make symptoms easier to manage.