Pregnancy nausea and vomiting are common, but there is a point at which “morning sickness” becomes much more than an unpleasant pregnancy symptom. Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting during pregnancy that can make it difficult or even impossible to eat, drink and carry out normal daily activities.
Unlike ordinary morning sickness, HG can cause significant dehydration, weight loss, electrolyte disturbances and nutritional deficiencies. Some women require treatment in a hospital, intravenous fluids or prescription anti-sickness medicines.
HG can also be emotionally exhausting. Constant nausea, repeated vomiting, difficulty eating and the inability to work or perform everyday tasks can affect the entire family.
The good news is that hyperemesis gravidarum can be treated and managed. Early recognition and appropriate medical care can reduce complications and help a pregnant woman get through the pregnancy more safely and comfortably.
What is hyperemesis gravidarum?
Hyperemesis gravidarum is the severe end of the spectrum of nausea and vomiting during pregnancy. It is characterised by persistent nausea and vomiting that interferes substantially with eating, drinking and normal activities.
There is no single universally accepted test or definition for HG. Healthcare professionals generally consider the severity and persistence of vomiting, inability to maintain adequate food and fluid intake, dehydration, weight loss and laboratory abnormalities when making the diagnosis.
A commonly recognised feature is loss of more than 5% of pre-pregnancy body weight, although the diagnosis should not depend on weight loss alone.
The condition affects approximately 0.3% to 3.6% of pregnancies, depending on the population and diagnostic criteria used.
Hyperemesis gravidarum vs morning sickness
Morning sickness is extremely common during pregnancy. It usually begins early in pregnancy and, for most women, improves by around 20 weeks.
HG is different because the symptoms are severe enough to affect hydration, nutrition and daily functioning.
| Morning sickness | Hyperemesis gravidarum |
|---|---|
| Usually mild to moderate | Often severe and persistent |
| Most women can eat and drink at least some food and fluids | Eating and drinking may become extremely difficult |
| Usually does not cause significant dehydration | Dehydration can occur |
| Major weight loss is uncommon | Significant weight loss may occur |
| Usually manageable at home | May require medication, IV fluids or hospital care |
| Usually improves with time | Can continue for many weeks or throughout pregnancy |
RCOG notes that ordinary pregnancy sickness usually starts between weeks 4 and 7 and settles by 20 weeks in about 9 out of 10 women. HG may be considerably more prolonged.
What is the main cause of hyperemesis gravidarum?
The exact mechanism of HG is still being studied, but our understanding has changed considerably in recent years.
One hormone receiving particular attention is growth differentiation factor 15 (GDF15). It is produced by the placenta and can influence appetite and nausea. Research suggests that differences in how strongly an individual’s body responds to GDF15 may help explain why some pregnant women develop much more severe symptoms than others. MedlinePlus now describes GDF15 as the main known driver of HG.
Other pregnancy-related hormonal changes, including hCG and oestrogen, may also contribute. Genetic susceptibility appears to play a role as well.
So, HG is not simply caused by eating the wrong foods, stress or a lack of willpower. It is a genuine medical condition associated with biological changes during pregnancy.
Is hyperemesis caused by the father?
No. Hyperemesis gravidarum is not caused by the father.
HG is primarily associated with pregnancy-related biological and hormonal factors, particularly signals involving the placenta and the pregnant person’s response to those signals. Genetic factors can influence susceptibility, but this does not mean that a father’s behaviour or actions caused the condition.
Partners can, however, play a very important role in helping someone cope with HG.
When does hyperemesis gravidarum start?
HG usually begins during the first trimester.
Symptoms commonly begin around 4 to 8 weeks of pregnancy, with many women noticing particularly severe symptoms around 6 weeks.
This timing overlaps with the period when pregnancy hormones are changing rapidly.
If severe vomiting starts much later in pregnancy, particularly after 16 weeks, healthcare professionals may investigate other possible causes rather than automatically assuming it is HG.
Who is more prone to hyperemesis gravidarum?
HG can occur in any pregnancy, but some factors are associated with a higher risk.
You may be more prone to HG if you:
- Had hyperemesis gravidarum during a previous pregnancy
- Have a close female relative who experienced HG
- Are pregnant with twins or higher-order multiples
- Have a history of motion sickness
- Have a history of migraine-associated nausea
- Are experiencing a molar pregnancy or gestational trophoblastic disease
- Have certain medical conditions, such as thyroid disease or diabetes
A previous history of HG is particularly important because the condition can recur in subsequent pregnancies.
What are the symptoms of hyperemesis gravidarum?
Symptoms can vary from one person to another, but common symptoms include:
- Severe, persistent nausea
- Frequent vomiting
- Difficulty keeping food or fluids down
- Significant weight loss
- Very dark urine
- Passing urine less frequently
- Dry mouth and intense thirst
- Weakness and extreme tiredness
- Dizziness or light-headedness
- Fainting
- Low blood pressure
- Headache
- Constipation
- Excessive salivation
- Electrolyte abnormalities
In severe cases, nutritional deficiencies can develop. Prolonged vomiting and inadequate nutrition can also cause thiamine (vitamin B1) deficiency, which can lead to the serious neurological condition Wernicke encephalopathy.
How long does hyperemesis gravidarum last?
There is no fixed duration.
Many women experience significant improvement during the second trimester. RCOG states that ordinary pregnancy sickness settles by 20 weeks in approximately 90% of women, but HG can last much longer.
HG symptoms commonly improve around 16 to 20 weeks, but some women continue to experience symptoms throughout pregnancy. StatPearls notes that approximately 20% of cases may continue throughout pregnancy.
In other words, there is no particular week at which HG always stops.
For some women, symptoms gradually become manageable. For others, medication and nutritional support may be necessary for much longer.
Does hyperemesis affect the baby?
In many cases, appropriate treatment allows the pregnancy to progress normally. HG does not automatically mean that the baby will be harmed.
However, severe or prolonged vomiting can result in dehydration, inadequate nutrition and significant maternal weight loss. These problems may increase the risk of lower birth weight, and some women with severe pregnancy sickness may require additional ultrasound monitoring of fetal growth.
This is one reason why HG should not simply be dismissed as “bad morning sickness.”
The objective is not only to stop vomiting. Treatment also aims to maintain adequate hydration and nutrition and protect the mother’s health.
Is hyperemesis a high-risk pregnancy?
HG can make a pregnancy medically higher risk, particularly when symptoms are severe or poorly controlled, but having HG does not automatically mean that the pregnancy will have a serious complication.
The level of risk depends on factors such as:
- Severity of vomiting
- Degree of dehydration
- Amount of weight loss
- Nutritional status
- Electrolyte abnormalities
- Response to treatment
- Other medical conditions
- Whether fetal growth is affected
Women with persistent or severe HG may require closer monitoring, including assessments of maternal weight, hydration and blood tests, and sometimes ultrasound monitoring of fetal growth.
What is the best treatment for hyperemesis gravidarum?
There is no single best treatment for every woman. Treatment is tailored according to the severity of symptoms and how well the person responds.
The main goals are to:
- Control nausea and vomiting
- Correct dehydration
- Replace electrolytes
- Prevent vitamin and nutritional deficiencies
- Maintain adequate nutrition
- Monitor the mother and baby when necessary
For mild symptoms, dietary adjustments and pregnancy-safe anti-sickness treatment may be sufficient.
For moderate or severe HG, treatment may involve prescription antiemetics, IV fluids and nutritional support. In some cases, hospital admission is required.
What is the first-line treatment for hyperemesis gravidarum?
The exact first-line medication can vary according to the guideline and the patient’s circumstances.
The 2024 RCOG guideline lists several first-line antiemetic options, including doxylamine with pyridoxine (vitamin B6), cyclizine, prochlorperazine, promethazine and chlorpromazine. Second-line options include medicines such as metoclopramide and ondansetron.
In the United States, ACOG also recognises vitamin B6 with or without doxylamine as an important treatment option for nausea and vomiting during pregnancy.
Do not start, stop or change anti-sickness medicines during pregnancy without discussing them with your obstetrician or other pregnancy care professional.
What are the treatment guidelines for hyperemesis gravidarum?
Current clinical management generally follows a stepwise approach.
1. Assess severity
The healthcare team evaluates:
- Vomiting frequency
- Ability to eat and drink
- Weight change
- Hydration
- Blood pressure and pulse
- Urine
- Electrolytes and other blood tests
- Possible alternative causes of vomiting
An ultrasound may also be used when appropriate, including to establish gestational age and check for multiple pregnancy or molar pregnancy.
2. Treat dehydration
Women who cannot maintain adequate fluid intake may need intravenous fluids.
Electrolyte abnormalities should also be identified and corrected.
3. Use anti-sickness medication
Different antiemetics may be used depending on symptom severity and response.
Sometimes more than one medication is required, under medical supervision. RCOG’s updated guideline provides a stepwise approach to antiemetic treatment.
4. Prevent thiamine deficiency
This is particularly important in prolonged vomiting or when IV fluids are required.
Thiamine supplementation may be necessary before or alongside glucose-containing treatment in women at risk of deficiency, because prolonged vomiting can lead to Wernicke encephalopathy.
5. Provide nutritional support when necessary
If adequate nutrition cannot be maintained, specialist nutritional support may be required.
Depending on the situation, this may include enteral tube feeding or, in selected severe cases, parenteral nutrition.
6. Provide emotional and practical support
HG can affect work, relationships, daily activities and mental wellbeing. RCOG specifically recognises the substantial emotional and social impact of pregnancy sickness and HG.
How can I stop hyperemesis gravidarum?
There is currently no guaranteed way to prevent or completely stop HG at home.
The most useful approach is early recognition and treatment.
If nausea is becoming severe, do not wait until dehydration and substantial weight loss develop before seeking help. Early treatment may prevent symptoms from becoming more difficult to control.
Practical measures that may help include:
- Eating small meals frequently
- Eating when nausea is least severe
- Keeping simple foods readily available
- Drinking small amounts frequently
- Avoiding known smell and food triggers
- Getting adequate rest
- Discussing anti-sickness medication early with your doctor
What foods help hyperemesis gravidarum?
There is no single HG diet that works for everyone. The priority is finding foods and fluids that the individual can tolerate.
Many people find the following easier to manage:
- Crackers
- Toast
- Plain biscuits
- Rice
- Potatoes
- Pasta
- Dry cereal
- Bananas
- Small portions of fruit
- Simple sandwiches
- Cold foods, if food smells trigger nausea
- Small amounts of protein-containing foods when tolerated
RCOG recommends small amounts of carbohydrate-rich, lower-fat foods such as potatoes, rice and pasta, while also recognising that individual triggers differ.
If smoothies, yoghurt, milk, dal or other nutritious foods are tolerated, they may help increase nutritional intake. The goal is not perfection; getting something down and keeping it down can be important during severe HG.
What foods should I avoid with HG?
Avoid foods that consistently trigger nausea or vomiting.
Common triggers can include:
- Greasy or fried foods
- Very spicy foods
- Heavy meals
- Foods with strong smells
- Very rich foods
- Any particular food that the individual has learned triggers vomiting
Cleveland Clinic notes that high-fat foods may worsen nausea for some pregnant people and suggests avoiding greasy or spicy foods when they are triggers.
It is also reasonable to temporarily prioritise tolerable foods over an ideal pregnancy diet when vomiting is severe. Nutritional requirements can be addressed progressively with help from the healthcare team.
How do people with hyperemesis gravidarum survive pregnancy?
For many women, managing HG becomes a day-to-day process rather than simply waiting for it to disappear.
Helpful strategies can include:
- Getting medical treatment early
- Taking prescribed medication consistently
- Drinking small amounts frequently
- Eating whatever nutritious foods can be tolerated
- Keeping track of weight and hydration
- Accepting practical help from family
- Taking time away from work when medically necessary
- Attending scheduled antenatal appointments
- Seeking psychological support when the condition becomes emotionally overwhelming
Some women need repeated outpatient treatment or hospital admissions. That does not mean they have failed to manage the condition. HG can be a serious medical illness requiring ongoing treatment.
How can I help my wife with hyperemesis gravidarum?
Partners can make a major practical difference.
Believe her
Severe HG is not simply ordinary morning sickness. Avoid comments such as “everyone feels sick during pregnancy” or “try to eat something.”
Take over everyday responsibilities
Cooking, grocery shopping, cleaning, childcare and other household responsibilities may become difficult. Taking these tasks off her shoulders can be extremely helpful.
Manage smells
Cooking smells, perfumes, cleaning products and even toothpaste can trigger nausea in some people.
Keep fluids and snacks available
Have several tolerable foods and drinks readily available so she does not need to prepare them herself.
Help with appointments
Offer to accompany her to medical appointments and keep track of medications and instructions.
Watch for dehydration
Dark urine, very little urine, dizziness, fainting, extreme weakness and inability to keep fluids down require medical attention.
Provide emotional support
HG can be isolating and exhausting. Listening without minimising the symptoms can be just as important as practical help.
What are 6 danger signs in pregnancy?
There are several recognised pregnancy danger signs. Six important ones include:
- Vaginal bleeding
- Severe headache, particularly with blurred vision
- Severe abdominal pain
- Convulsions or seizures
- Fever with severe weakness or feeling very unwell
- Fast or difficult breathing
WHO guidance identifies these as signs requiring prompt emergency assessment.
Other warning signs include leaking fluid, reduced fetal movement later in pregnancy, severe swelling, fainting and persistent vomiting.
For someone with suspected HG specifically, being unable to keep fluids down, very little or dark urine, fainting, severe dizziness or significant weakness should also prompt urgent medical assessment.
When should you seek medical help for hyperemesis gravidarum?
Contact your obstetrician or maternity service if:
- You cannot keep fluids down
- You are vomiting repeatedly throughout the day
- You are losing weight
- You are passing very little urine
- Your urine has become very dark
- You feel faint or extremely dizzy
- You cannot carry out normal daily activities
- You have blood in your vomit
- You develop abdominal pain or fever
- Your symptoms suddenly become worse
Severe dehydration and nutritional deficiencies can become dangerous if HG is left untreated.
Frequently asked questions about hyperemesis gravidarum
How long does hyperemesis gravidarum last?
It varies. Symptoms often improve between 16 and 20 weeks, but some women continue to experience HG throughout pregnancy.
What is the best treatment for hyperemesis gravidarum?
Treatment depends on severity. It may include dietary measures, anti-sickness medication, IV fluids, electrolyte replacement, thiamine and nutritional support. Severe cases may require hospitalisation.
What is the main cause of hyperemesis gravidarum?
Current evidence strongly implicates pregnancy-related hormonal signalling, particularly GDF15 produced by the placenta. hCG and other hormonal and genetic factors may also contribute.
Is hyperemesis caused by the father?
No. HG is associated with pregnancy-related hormonal and biological factors. A partner does not cause HG.
Does hyperemesis affect the baby?
Severe, prolonged HG can be associated with lower birth weight and may lead to additional fetal growth monitoring. Appropriate treatment helps reduce the risks associated with dehydration and poor nutrition.
What foods help hyperemesis gravidarum?
Small amounts of bland, carbohydrate-rich foods such as rice, potatoes, pasta, crackers and toast may be easier to tolerate. However, individual tolerance is more important than following a rigid food list.
What foods should I avoid with HG?
Avoid foods, smells and drinks that reliably trigger nausea. Greasy, fatty and spicy foods are common triggers for some people.
What week of pregnancy does hyperemesis start?
HG commonly begins around 4 to 8 weeks, often becoming noticeable around 6 weeks.
Who is more prone to hyperemesis gravidarum?
Risk is higher in women with previous HG, a family history, multiple pregnancy, motion sickness, migraine-associated nausea or certain pregnancy conditions.
How can I stop hyperemesis gravidarum?
There is no guaranteed home method to stop HG. Early medical assessment, appropriate anti-sickness medication, hydration, nutritional support and avoiding individual triggers can help control symptoms.
How do people with hyperemesis gravidarum survive pregnancy?
With early treatment, ongoing medical monitoring, appropriate medication, hydration and nutritional support, many women manage HG through pregnancy. Some require outpatient treatment or hospitalisation, particularly during severe episodes.
What is the first-line treatment for hyperemesis gravidarum?
There isn’t one universal first-line drug for every patient. RCOG lists doxylamine/pyridoxine and several other antiemetics among first-line options, with treatment selected according to the individual’s symptoms and circumstances.
Is hyperemesis gravidarum a high-risk pregnancy?
HG can increase pregnancy risks when severe, especially if it causes dehydration, significant weight loss or nutritional deficiencies. Some pregnancies require closer maternal and fetal monitoring, but HG does not automatically mean that a serious complication will occur.
Hyperemesis gravidarum: the key takeaway
Hyperemesis gravidarum is more than ordinary morning sickness. Persistent vomiting can lead to dehydration, weight loss, electrolyte abnormalities and nutritional deficiencies, making early medical attention important.
The condition usually starts during early pregnancy, often around 4 to 8 weeks. While many women improve by the second trimester, HG can persist much longer and occasionally continue until delivery.
Treatment may involve dietary adjustments, pregnancy-safe antiemetic medicines, IV fluids, electrolyte replacement, thiamine and nutritional support. Severe cases may require hospital care.
If a pregnant woman is unable to keep fluids down, is passing very little or dark urine, feels faint or has significant weight loss, she should speak with her obstetrician or seek medical assessment rather than trying to manage severe symptoms alone.
At Sparsh Diagnostic Centre, pregnancy-related diagnostic services and ultrasound examinations can form part of the monitoring recommended by the treating obstetrician. For suspected hyperemesis gravidarum, however, medical assessment by an obstetrician is the priority, particularly when dehydration or significant weight loss is present.
Medical note: This article is intended for general health education and does not replace consultation with an obstetrician or other qualified healthcare professional. Medication doses and treatment decisions should always be individualised by the treating doctor.
To consult a Gynecologist at Sparsh Diagnostic Centre, call our helpline number 9830117733.
#BhaloTheko
Disclaimer:
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
Sources and further reading
- National Center for Biotechnology Information – Hyperemesis Gravidarum — clinical overview, causes, risk factors, diagnosis and treatment.
- Cleveland Clinic – Hyperemesis Gravidarum — symptoms, risk factors, complications and treatment options.
- MedlinePlus – Hyperemesis gravidarum — causes, symptoms, tests, treatment and prognosis.
- RCOG – Pregnancy sickness and hyperemesis gravidarum — patient-focused guidance on symptoms, duration, treatment and fetal monitoring.
- RCOG – Green-top Guideline No. 69 — clinical guidance for management of nausea, vomiting and HG.
- ACOG – Nausea and vomiting of pregnancy — patient guidance on pregnancy nausea, vomiting and when treatment is needed.
