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Nausea and vomiting in pregnancy—hyperemesis gravidarum

What is nausea and vomiting in pregnancy?

Nausea and vomiting in pregnancy (NVP) is very common and affects up to 80% of pregnant women. It typically begins early in pregnancy (around the 4th–7th week), peaks at the 9th week and settles in most cases by 20 weeks. Occasionally, it can last until the end of pregnancy. A small number of women may suffer with more severe or prolonged symptoms which require hospital treatment. NVP can affect you at any time of day or night.

The exact cause of NVP is not fully understood, but it is thought to be related to hormonal changes. We also do not know why some women get it worse than others. However, it is more likely if:

  • You have had it before
  • You are having more than one baby (twins or triplets)
  • You have a molar pregnancy (a rare condition where the placenta overgrows and the baby does not form correctly)

Other causes of vomiting also need to be excluded like a kidney infection, gastritis (inflammation of the stomach), appendicitis or gastroenteritis.

What is hyperemesis gravidarum?

In its most severe form, NVP can lead to severe dehydration and significant weight loss. This is called hyperemesis gravidarum (HG)and it affects up to 3% of all pregnancies. The majority of women with HG require hospital treatment at some point.

There is no evidence that NVP affects the baby in any way. If you have severe, prolonged NVP or HG in pregnancy, you might be offered extra growth scans later on in the pregnancy if felt necessary by your obstetrician or midwife. 

Hyperemesis Gravidarum treatment in the AEC

If you have been treated for Hyperemesis Gravidarum in one of our AECs, we would like to hear from you—please take a short survey.

How will it make me feel?

Nausea and vomiting is unpleasant and can significantly affect your day-to-day life. We know it can affect your mood, your work and your home life, including your ability to look after your family or loved ones.

How is HG diagnosed?

There is no specific test. The doctor or nurse will make an assessment of how dehydrated you are. The following tests will be performed:

  • A questionnaire about your symptoms
  • Urine test
  • Blood tests
  • General health check including blood pressure, pulse, respiratory rate and temperature
  • Baseline weight check

What treatment will I require?

If you are unable to tolerate fluids, you will require fluid replacement through a vein in your arm given over a short period of time. In addition, you will be offered anti-sickness medication, called anti-emetics. These can be given by mouth, by injection (again through a vein or rarely into a muscle) or as a suppository. We also recommend Thiamine (Vitamin B1) replacement given initially as a drip and high dose Folic acid. You may also require an antacid drug such as omeprazole to protect the stomach lining, especially if you see blood in your vomit.

Pregnant women are at increased risk of developing blood clots in the legs (deep vein thrombosis) and in the lungs (pulmonary embolus). This risk increases if you are dehydrated and less mobile. To reduce your risk of developing blood clots with NVP or HG, you will be advised to wear compression stockings and for most women, heparin injections will also be advised to help to thin the blood. These injections are usually given whilst receiving treatment during an admission to hospital but also during outpatient management and in some cases after hospital discharge until the HG resolves.

What anti-sickness medication is offered?

Every pregnancy is different and not all medications will work for every woman. There are a variety of anti-emetics that you might be offered, either alone or as a combination. Not all of them are licensed for use in pregnancy but there is no evidence that they cause harm to your baby. These might include:

  • Cyclizine is usually the first choice of anti-emetic. It can be given orally or by injection into the vein or muscle.
  • Prochlorperazine and promethazine can also be used when cyclizine alone does not work. They can either replace cyclizine or be used in combination.
  • Metoclopramide or Ondansetron  are also used if deemed appropriate  anti-emetic drugs but there are some limitations to their use which medical staff will explain to you. 
  • As a last line treatment, corticosteroids might need to be used if you develop resistant symptoms despite receiving the above medications.

Where will my treatment happen?

Recent evidence from clinical trials has shown that women who receive treatment for NVP and HG as an out-patient (i.e. do not stay in hospital) recover as quickly as women who stay overnight in hospital. This is known as ambulatory treatment and will be provided in Ambulatory Emergency Care (AEC) Unit. Initiation of treatment may start in the hospital Emergency departments, if you are first seen there. 

Will I need to stay in hospital?

Only a few women will need to be admitted to hospital. If you have abnormal blood tests, a co-existing medical condition, weight loss over 5% of your pre-pregnancy weight or you are unable to tolerate oral anti-emetics you might need to stay in hospital.

Will I require an ultrasound scan?

If you have not had an ultrasound scan in your pregnancy by the time you are receiving treatment for NVP/ HG, the Early Pregnancy Unit will arrange one for you. Your treatment is the most important aspect of caring for you and therefore your scan might not happen on the first day you present to the hospital.

What can I do to help?

It is important to stop all medications which may make your symptoms worse. Iron tablets are particularly known for this. However, this must be discussed with a doctor prior to doing so.

Eat little and often. Plain foods are usually easier to tolerate (biscuits, crackers, bread, and potatoes). Citrus (fruit and vegetables) and spicy based foods can make your symptoms worse. Drink small sips of fluid throughout the day. It is important to try and maintain oral intake of fluids when you are away from the hospital. Some women may find fizzy drinks or flavoured water are better tolerated when compared to plain water.

Ginger based products might help some women with mild to moderate NVP. Some women benefit from alternative therapies such as acupressure or acupuncture.

After discharge

When you have received the treatment in hospital, you will be given a supply of oral anti-emetics to take home.

If you are still having ambulatory treatment nursing staff in AEC will contact you the next day to make a telephone assessment of your symptoms and to see if you need to come back for further treatment in AEC or need to be admitted to hospital. Please inform nursing staff if you will not be able to keep the follow-up appointments you are offered. If you fail to attend, we may unfortunately need to discharge you to your GP if we cannot get hold of you by phone after 3 attempts. (Please inform staff if you do not want to share your medical information with your GP.) When you start to feel better, you can discuss with your healthcare professional or GP when to start reducing the number of tablets you are taking. 

If you are discharged home and your symptoms return or get worse, you should sip fluids regularly and take the anti-emetics as they were prescribed for you. You should ask your GP for a repeat prescription before your medications run out. Use the telephone numbers in this leaflet to contact us for advice or if you are unsure about anything related to your treatment. You can also self-refer back to AEC after discharge if you were known to our Service but only during the same pregnancy.

Contact information

Chelsea and Westminster Hospital

Annie Zunz Ward
24-hour advice line
T: 020 3315 3906 or 07825 504 630

Ambulatory Emergency Care (AEC)
T: 020 3315 3564

Elizabeth Suite (for scans)
Early Pregnancy and Acute Gynaecology Unit
020 3315 5073/5070   

West Middlesex University Hospital

Early Pregnancy Unit
Mon–Fri, 8:30am–5pm
T: 020 8321 6812 or 07920 020 800

Further information

The following websites can be referred to for further advice and support:

George Vasilopoulos