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Hyperemesis gravidarum (HG)

Patient information A-Z

Who is the leaflet for? What is its aim?

This leaflet aims to give you information about hyperemesis gravidarum (HG), what it is and how it can be treated, to help you understand the condition.

It includes information on:

  • the signs and symptoms
  • aim of treatment
  • how the condition is managed


Bring all of your medicines (including inhalers, injections, creams, eye drops or patches), and a current repeat prescription from your GP.

Please tell the staff about all of the medicines you use. If you wish to take your medication yourself (self-medicate) during your stay then ask your nurse. Pharmacists visit the wards regularly and can help with any medicine queries.

What is hyperemesis gravidarum?

Nausea and vomiting in early pregnancy is very common and affects most women to some degree. It usually settles by 16-20 weeks, although it can last longer in some women and does not have an adverse effect on the mother or baby. However, if the nausea and vomiting is severe and persistent to the extent that you are unable to keep food or liquid down, you have lost more than 5% of your pre-pregnancy weight, and are dehydrated and have an imbalance of the electrolytes (salts) in your blood, this is called ‘hyperemesis gravidarum (HG)’.

Hyperemesis gravidarum can affect up to 3.06% of all pregnancies. It generally clears after the first 16-18 weeks of pregnancy, but for some women it can continue throughout their pregnancy. It affects just a small percentage of pregnant women but there is a high risk of it recurring in future pregnancies.

You will be assessed in Clinic 24 during ‘office hours’ (08.00 - 20.00 hours, Monday to Friday) or out of hours in the Emergency Department. We aim to treat you as a Day case on Daphne ward where you will be given intravenous fluids and anti-emetics (medication to reduce nausea and vomiting). If you are still unwell following this management you will be admitted to an inpatient bed Daphne Ward for further care. If your symptoms persist after 14 weeks gestation your care may be transferred to our maternity triage Clinic 23 and if you require admission you will be admitted to Sara ward.

What are the causes?

The cause is unknown; however, it is believed to be due to hormonal changes in pregnancy.

What are the signs and symptoms?

  • inability to keep down food or water
  • unintentional weight loss
  • dizziness and fainting
  • prolonged and severe nausea and vomiting
  • passing a lower volume of or more concentrated urine
  • inability to swallow saliva
  • feeling dry

How will it make me feel?

HG can be difficult to cope with. It can affect your mood, your work and your home situation. Friends and family support can help. If you are finding that you feel persistently down, please speak to your nurse/midwife.

What does the assessment involve?

  • A discussion about your symptoms:
    • how long you have had them
    • what you are managing to eat or drink
    • medications you are on
    • any weight loss
    • previous pregnancies
    • whether you have any abdominal pain or urinary symptoms
  • a set of observations, including temperature, pulse, respiratory rate, blood pressure and oxygen saturations
  • an abdominal examination (if you have pain)
  • height and weight
  • urine test
  • blood tests, including a prick test of your finger to assess your glucose levels
  • An ultrasound if no previous scan in this pregnancy. This is to check how many weeks pregnant you are. It will also check for multiple pregnancies and possible other factors for HG. (This may not happen until the next working day)

Why do we test your urine?

During your assessment (and admission if required) we will test your urine for the presence of ketones. Ketones are toxic acidic chemicals in your urine. Ketones are produced when you are unable to keep food down and your body has to break down fat for energy. Ketones are an indication of the severity of dehydration.

What is the aim of treatment for hyperemesis gravidarum?

Treatment aims to:

  • rehydrate
  • break the cycle of vomiting that leads to dehydration
  • ensure there are no other causes for the nausea and vomiting

How will I be treated?

Day case care:

If you meet certain criteria when you are assessed you will be offered day case management. This involves:

  • Observations taken every hour.
  • Testing your urine every time you pass urine therefore we ask you let staff know if you need to pass urine and they will give you a container to use.
  • fluid replacement to correct dehydration:
    • This will be given through a drip in your arm.
  • anti-sickness medication:
    • This can be given through the drip in your arm, as an injection or as a tablet.
    • You may need a combination of medications to control your symptoms.
  • You may be given H2 receptor antagonists or proton pump inhibitor medication (antacids). These can be given through your drip or as a tablet.
  • You will be given anti-embolic stockings to wear and possibly an injection of an anticoagulant to reduce the risk of blood clots.

We will allow you home once your urine test is normal and you are able to tolerate some oral diet and fluids.

Inpatient care:

If the above treatment is not as effective as both we and you would wish and if you meet certain criteria you will be offered inpatient management. This involves the above treatments plus the following:

  • observations taken every 1-2 hours
  • daily weight
  • daily blood tests
  • You may be referred to the dietician for further support in managing your hyperemesis gravidarum.
  • Consideration of a PICC line, this is a long hollow tube made of silicon rubber which is placed into one of the large veins in the arm. One end of the line comes out from the arm and can be used for injections and the other end is positioned inside a large vein, usually near to the heart. This is a method of giving intravenous fluids directly into your circulation and this can stay in for up to six months. It negates the need to have a new cannula (drip) placed into your arm on every admission.
    • If you have a PICC line sited you will require weekly dressings whilst it is in place. This can be done on any of your hospital visits or by your practice nurse.
  • Steroid treatment
  • Vitamins either orally or through your drip
  • If you are unable to tolerate anything orally for 5 days you will be referred to the parenteral nutrition (PN) team for possible feeding by the PICC line. This is a different way of providing all the nutrients your body needs whilst you cannot eat. It is introduced directly into the blood stream, bypassing the digestive system.
    • If you have PN feeding you will have a finger prick performed daily.

We will allow you home once your urine tests are normal and you are able to tolerate some diet and fluids.


The aim of the treatment is to make you feel better physically and emotionally by allowing you control over your nausea and vomiting in order to continue with your day to day life.


Should you require a drip or PICC there is a risk of infection and/or bruising. These risks are minimised by use observance of appropriate techniques when a cannula or PICC line are inserted.

Women with HG are at an increased risk of blood clots as the blood can be thicker. We therefore aim to minimise this risk by giving you anti-thromboembolic injections and asking you to wear anti-embolic stockings.


The alternative to this treatment is to decline treatment. The consequences of this will be discussed with you.

Advice for discharge

On discharge you will be given oral medication to help control the nausea and vomiting. We recommend that you take any medication you are given regularly and not as you need it as this will help it to be more effective. You will need to see your GP for repeat prescriptions.

Practical tips to help at home:

  • Try eating little and often throughout the day
  • Take your time with meals: try to relax and eat slowly
  • Avoid fizzy or caffeinated drinks
  • Drink plenty of fluids
  • Avoid triggers such as rich, spicy or fatty food
  • Cold food options may be easier to manage
  • Get some fresh air and exercise daily
  • Avoid wearing tight fitting clothes

Contacts and further information

If you have any further questions or anxieties at any time, please feel free to ask a member of staff including:

Clinic 24 (early pregnancy unit)

01223 217636
08:00 – 20:00 Monday to Friday
08:30 – 14:00 at weekends
Closed bank holidays

Daphne ward (inpatient gynaecology ward)

01223 257206
At all other times
You can also attend the emergency department (ED) at any time if you are concerned and clinic 24 is closed.

Clinic 23

01223 217217

Sara ward

01223 217671

Pregnancy sickness support

024 7638 2020

References and sources of evidence

Privacy and dignity

Same sex bays and bathrooms are offered in all wards except critical care and theatre recovery areas where the use of high-tech equipment and/or specialist one to one care is required.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

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Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151