Hyperemesis Gravidarum (Excessive nausea and vomiting in pregnancy)

Patient Experience

  • Reference Number: HEY-579/2022
  • Departments: Gynaecology
  • Last Updated: 1 May 2022


This leaflet has been produced to give you general information about hyperemesis gravidarum (excessive nausea and vomiting in pregnancy).  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and your doctor but may act as a starting point for discussion. If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

What is hyperemesis gravidarum?

Nausea and/or vomiting is common in pregnancy and affects three in four pregnant women. It usually begins around the sixth week of pregnancy and generally starts to settle by about the 13th or 14th week.  However, one in ten women may continue to feel sick after the 20th week of pregnancy. 

Hyperemesis gravidarum is excessive nausea and vomiting in pregnancy. It affects approximately 1 in 200 pregnant women, although nausea and vomiting are both very common in early pregnancy (affecting 6 or 7 out of 10 of pregnant women). Hyperemesis gravidarum is prolonged and severe nausea and / or vomiting, which can lead to dehydration and weight loss. 

What causes hyperemesis gravidarum?

The exact cause of nausea and vomiting in pregnancy is not known. However, a number of different causes have been suggested, including:

Increased oestrogen levels – during pregnancy, the female sex hormone levels (oestrogen) begin to rise. They tend to be at their highest during the first three months when these symptoms are at their worst. 

Increased hCG levels – after conception (when the sperm fertilises the egg), the body begins to produce a hormone called human chorionic gonadotrophin (hCG). It is thought that this rise may cause nausea and vomiting during pregnancy.

Nutritional deficiency – especially a lack of vitamin B6.

Gastric problems – the hormone progesterone which is produced in pregnancy to prepare the womb, may reduce the movement within the stomach and small intestine, resulting in nausea and vomiting.

Psychological influences – this theory is not supported by research. It is now thought that psychological symptoms are likely to be the result rather than the cause of nausea and vomiting in pregnancy.

What can I do to help?

By altering certain lifestyle, eating and drinking habits, you may be able to help reduce your symptoms.

The following is a list of measures that have been shown to be helpful:

  • Drink little and often rather than in large amounts.  Avoid fizzy and caffeinated drinks (including tea and coffee)
  • Avoid drinks that are cold, tart (sharp) or sweet
  • Avoid meals very early and very late in the day, although sometimes eating a plain biscuit before getting up may help.  Eat smaller, more frequent meals that are high in carbohydrate and low in fat (savoury foods, such as toast, crackers and crisp-bread, are usually better tolerated than sweet, spicy or greasy foods)
  • Avoid food or strong smells that trigger your symptoms (occasionally even your own perfume)
  • Stop smoking (and ask your partner to stop smoking around you)
  • Stop taking iron tablets (you can start again after the vomiting stops)
  • Stop the use of all non-prescription medicines (including herbal remedies)
  • Avoid stressful situations by trying not to do too much
  • Get plenty of rest, because tiredness can make nausea worse
  • Wear comfortable clothes without tight waistbands, which can sometimes make you feel uncomfortable
  • Acupressure bands, which are special bands placed around the wrist (often used in travel sickness) have also been found to help with pregnancy related sickness
  • Ginger – there is some evidence that ginger supplements may help reduce the symptoms, however check with your nurse, doctor or pharmacist before using
  • Can also use slimming aids / build up shakes to get calories and nutritional needs as full of vitamins and minerals.

When should I seek medical help?

Any affected woman who finds it difficult to eat and/or drink or who persistently vomits after eating or drinking should seek medical help. You should always contact your GP first, who will then refer you on to hospital if necessary. You should seek medical help urgently if you develop any of the following:

  •  Unable to keep food or fluids down for 24 hours
  •  Weight loss
  •  Dizziness and/or fainting

How do we treat hyperemesis gravidarum?

You will be seen by a nurse and a doctor who will ask you some questions and complete the following checks:

  • Record your weight
  • Test your urine
  • Perform blood tests- FBC/BCP
  • Arrange an ultrasound scan (if not done already) to check that your baby is fine. If already had a scan a rescan will not be performed.

The results of all these tests will help the medical staff to decide the best treatment option for you.

Treatment of hyperemesis gravidarum at home

Whenever possible, we prefer to treat women with hyperemesis gravidarum as outpatients at home, as most women respond well, and recovery is often better in your own home environment.  Avoiding hospital admission reduces the risk of acquiring infections that are more common in hospital. If you can be treated in this way, we will give you specific advice on how to help yourself.  We will also give you anti-sickness medicines. If you do not get better with treatment at home, we would recommend you are treated as an inpatient.

Outpatient Treatment of hyperemesis gravidarum

Sometimes we treat patients with hyperemesis gravidarum in hospital but as an outpatient, but your stay is only approximately a 4-6 hour programme. This is where you are seen and assessed by the nurse. Relevant tests such as urine, blood, weight and USS (Ultrasound Scan) ordered, if you have not had an USS already. If you are not well enough to be discharged home, but meet the criteria for outpatient management, then normally hospital treatment involves replacing lost body fluid through an intravenous drip and injecting medicines directly into your muscles. We will monitor you for approximately 4-6 hours.  If you feel better after this treatment we will send you home with anti-emetics, (a drug administered to treat sickness) and open access for advice should your symptoms worsen.

Inpatient treatment of hyperemesis gravidarum

Admission to hospital is necessary for women with very severe symptoms such as excessive weight loss (more than 5% of body weight), muscle wasting, dehydration, dizziness and palpitations, those with abnormal test results, and women who do not respond to outpatient treatment. We will perform additional blood and urine tests, sometimes as often as daily. Hospital treatment involves replacing lost body fluid through an intravenous drip and injecting medicines directly into your muscles.

Anti-sickness medication in pregnancy

Due to complex regulations, most medications are not licensed for use in pregnancy. This is mainly due to a lack of clinical trials amongst pregnant women. Prescribing of medications in pregnancy always follows a careful assessment, which weighs the risks against the benefits. Medication with the best safety and effectiveness record over time is usually chosen as first line treatment. The benefits of treating hyperemesis gravidarum outweigh the potential risks of treatment.

Anti-sickness medication can be given by mouth or by an injection into your leg. These medicines, used in combination with the self-help measures detailed above can be very successful in treating hyperemesis gravidarum.


If it is appropriate, you will have an ultrasound scan. This is to make sure the pregnancy is progressing well and to check in case of multiple pregnancies.

What can I do to help myself at home?

Eating and drinking

Try to follow a diet that is light, frequent and high in carbohydrates but low in fat, protein and spices, as this will be easier for you to digest. Eat only when you are hungry. Drink plenty of water and non-acidic fruit juices to keep hydrated.

Food and drinks such as herbal teas containing ginger, peppermint and fennel aid digestion and sooth inflammation in the stomach. Also try other drinks and snacks with ginger in them, crackers, toast (dry), jelly and frozen desserts. Incorporate other foods once you feel you can tolerate them.


The key for the hyperemesis gravidarum sufferer is rest. Hyperemesis gravidarum is an episodic condition which means you will have frequent periods of recovery and relapse. The temptation when you do feel better is to rush to catch up with the jobs that you could not do when you were too ill.  Unfortunately doing to much can cause a relapse.  It is important that you try to get help from family and friends to help with housework and childcare.

Avoid triggers of nausea

Many women find that sensory stimulation such as loud noise, moving visual images or bright light, strong smells and even the movement of air from an open window can all trigger vomiting. At all costs avoid triggers of nausea. Strong aversions to various foodstuffs and food smells are common in most if not all women suffering from hyperemesis gravidarum. For some the slightest thing will trigger nausea, including even the sight of food or hearing someone talking about it. Many women find that once they have vomited a certain food, they cannot bear the sight of it again until the hyperemesis gravidarum improves. For some women an aversion can have such a strong association that they still cannot eat certain things even after the pregnancy. Cooking smells are often unbearable so avoid cooking as much as possible and make sure that windows are open, and you are far from the kitchen while it is going on.

How to manage hyperemisis gravidarum

It is important for you to understand that hyperemesis gravidarum is due to your pregnancy and has not arisen because of anything you have done or failed to do. Family help and support is very useful at times like this and we would encourage you to share the information contained here with your partner and other family members.

Although it might not appear so now, the condition does resolve on its own, usually from about week 14 of your pregnancy.

Hyperemesis gravidarum is actually a sign that your pregnancy hormone levels are good, and this reflects a healthy pregnancy.  You can be reassured that we know from research that, if treated properly, this condition is very unlikely to be harmful to you or your baby.  Please feel free to discuss any anxieties you may have with the nurse or doctor looking after you.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Early Pregnancy Assessment Unit / Emergency Gynaecology Unit Telephone number (01482) 608767

Useful contacts and websites

HER Foundation: http:// www.hyperemesis.org

Pregnancy Sickness Support


Information on Gynaecology Services at Hull University Teaching Hospitals NHS Trust can be found at: https://www.hey.nhs.uk/gynaecology

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

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The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

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