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Pregnancy sickness (nausea and vomiting of pregnancy and hyperemesis gravidarum)

This information is for you if you want to know more about nausea and vomiting of pregnancy or about hyperemesis gravidarum, which is the most severe form of the condition. It may also be helpful if you are a relative or friend of someone who is in this situation.

The information here aims to help you better understand your health and your options for treatment and care. Your healthcare team is there to support you in making decisions that are right for you. They can help by discussing your situation with you and answering your questions.

Within this information we may use the terms ‘woman’ and ‘women’. However, we know that it is not only people who identify as women who may want to access this information. Your care should be appropriate, inclusive and sensitive to your needs whatever your gender identity.

A glossary of all medical terms is available.

Key points

  • Nausea and vomiting of pregnancy is a common condition that settles by 20 weeks in 9 out of 10 pregnant women.
  • Hyperemesis gravidarum is a severe form of this condition and can affect up to 3 in 100 pregnant women.
  • Nausea and vomiting and hyperemesis gravidarum can affect your mood, your work, your home and your social life.
  • While most women can be treated at home or as outpatients in hospitals, 1 in 5 affected women may need admission to hospital for treatment.
  • Several different anti-sickness medicines are available that may help your symptoms. While some of these medicines may not be licensed for use in pregnancy, they are considered safe for you and your baby.

Nausea and vomiting are symptoms of pregnancy that affect most women. It starts early in pregnancy, usually between the 4th and 7th week. It settles by 20 weeks in 9 out of 10 women, although in some women it may last longer. It is often called ‘morning sickness’ but it can occur at any time of the day or night.

The cause is thought to be hormones which are produced in pregnancy in all women. Research suggests that some women get pregnancy sickness worse than others due to genetic differences, which causes them to have higher levels of a hormone called GDF-15. GDF-15 is a hormone produced by the placenta that causes a loss of appetite and nausea.

You are more likely to have pregnancy sickness if:

  • you have had it before
  • you are having more than one baby (twins or triplets)

It is important that other causes of vomiting are considered and looked into, particularly if:

  • you have pain in your tummy or
  • you have other symptoms for example pain passing urine
  • you have had other medical conditions for example a stomach ulcer or gall stones, or
  • your vomiting only starts after 16 weeks of pregnancy.

If the nausea and vomiting becomes so severe that it stops you from doing your daily activities and you are unable to eat and drink normally, it is known as hyperemesis gravidarum. This may affect up to 3 in 100 pregnant women.

It can cause you to become dehydrated. Signs of dehydration include feeling ‘dry’ or very thirsty, becoming drowsy or unwell, or your urine changing from a light yellow to a dark yellow or brown colour. Women with this condition may need to be admitted to hospital.

Nausea and vomiting of pregnancy can be a difficult problem to cope with. It can affect your mood, your work, your home situation and your social life. Support from family and friends can help. In some women, the symptoms can be so severe that they become depressed and need extra support such as counselling. If you find that you feel down then you should speak to your healthcare professional.

There is no evidence that mild to moderate nausea and vomiting have a harmful effect on your baby.

Women with severe nausea and vomiting or with hyperemesis gravidarum may have a baby with a lower than expected birthweight. You may be offered scans to monitor the growth of your baby.

Most women with nausea and vomiting of pregnancy will be able to manage their symptoms themselves. You could:

  • eat small amounts of foods that are high in carbohydrate and low in fat, such as potato, rice and pasta, or foods that are easier to tolerate such as plain biscuits or crackers
  • avoid any foods or smells that trigger symptoms.

If your symptoms do not settle or if they stop you doing your daily activities, see your GP. They can prescribe anti-sickness medication that is safe to take in pregnancy.

Contact your GP or your midwife. They will arrange for you to be seen in the assessment unit at your hospital. This may be in the maternity department or be part of the gynaecology unit. You can also get advice by contacting NHS 111.

You will be offered a check-up that may include:

  • a discussion about how long you have had your symptoms for and whether:
    • you are keeping fluids and food down
    • you have tried any medication
    • you have lost weight rapidly
    • you have any other symptoms
    • you have had this in a previous pregnancy
  • a check of your general health including your temperature, pulse, breathing rate and blood pressure; you will be offered to have your weight measured and an assessment of whether you are dehydrated or undernourished.
  • urine tests to look for infection
  • blood tests
  • an ultrasound scan if you have not had one yet in the pregnancy. This is to check how many weeks pregnant you are. It will also check for twins. If you are able to keep some fluids down but are unable to drink enough, you should be offered fluids through a drip in your arm over a short period of time. This is called rapid rehydration. You will also be offered anti-sickness medication. Many women feel much better after this and are able to go home.

Admission to hospital may be advised if you:

  • are dehydrated
  • have severe vomiting and are unable to keep any fluids or oral medication down
  • have abnormal blood tests
  • have lost a lot of weight rapidly
  • have a medical condition such as a heart or kidney problem, diabetes, epilepsy or HIV and unable to take medicine orally.

You will be given fluids through a drip in your arm. This will be continued until you are able to drink fluids without vomiting.

Each day how much you drink and how much urine you are passing will be measured. Your temperature, blood pressure, pulse, breathing rate and weight will also be recorded.

You should be offered:

If you are taking iron medication, this can be stopped temporarily because it can make sickness worse.

When you are feeling better, you can start to drink and eat small amounts and slowly build up to a normal diet.

There are several different types of anti-sickness medicines that you may be offered.

  • An oral medication that is a slow-release combination of doxylamine and pyridoxine (vitamin B6) called Xonvea™ is the only licensed treatment of nausea and vomiting in pregnancy in the UK.
  • Cyclizine can be taken by mouth or by an injection. Prochlorperazine, chlorpromazine and promethazine can also be tried if cyclizine has not worked.

All the medications above are considered to be safe in pregnancy. Occasionally, you may require a combination of two or more anti-sickness medications.

  • Metoclopramide, domperidone and ondansetron are other medications that may be prescribed for nausea and vomiting and can be taken by mouth or by an injection. These are also considered safe to use in pregnancy. They are usually used if the previous medications have not worked. This is due to a small risk of side effects. Your health care professional can discuss this with you.
  • Corticosteroids may also be considered if:
    • you are still suffering from hyperemesis gravidarum despite fluids being given through a drip and regular anti-sickness medication has not helped
    • you have lost a lot of weight.

Corticosteroids are successful in helping nausea and vomiting in many women where all other measures have not helped. Most women will be able to stop corticosteroids by 18–20 weeks but a few women will need to continue them at a low dose for the rest of the pregnancy. If you are taking corticosteroids, you will be offered a test for gestational diabetes.

If hyperemesis gravidarum is not treated, it may cause more harm to the baby than any possible effects of a medicine recommended by your doctor.

You will be offered anti-sickness tablets to take home. If you feel better, you can cut down the number of tablets. If your vomiting gets worse, you may put eating on hold but try to keep sipping fluids and taking the anti-sickness tablets until you start to feel better. Ask your GP for a repeat prescription before your tablets run out.

Your symptoms may return and you may become dehydrated. If this happens, contact your midwife, GP or maternity unit to be assessed again.

If you have ongoing severe nausea and vomiting after 20 weeks, contact your midwife or GP. They may offer you ultrasound scans to monitor the growth of your baby in later pregnancy.

Although this can be a difficult situation for you and may affect you throughout your pregnancy, the symptoms usually resolve or improve after your baby is born. If you have any ongoing concerns, contact your midwife or GP for advice and support.

Having pregnancy sickness can be stressful and can affect your mental wellbeing. If you are feeling anxious, depressed or worried in any way, please speak to your healthcare team who can answer your questions and help you get support. The support may come from healthcare professionals, voluntary organisations or other services. Further information and resources are available on the NHS website.

Shared Decision Making

If you are asked to make a choice, you may have lots of questions that you want to ask. You may also want to talk over your options with your family or friends. It can help to write a list of the questions you want answered and take it to your appointment.

Ask 3 Questions

To begin with, try to make sure you get the answers to 3 key questions, if you are asked to make a choice about your healthcare:

  1. What are my options?
  2. What are the pros and cons of each option for me?
  3. How do I get support to help me make a decision that is right for me?

*Ask 3 Questions is based on Shepherd et al. Three questions that patients can ask to improve the quality of information physicians give about treatment options: A cross-over trial. Patient Education and Counselling, 2011;84:379-85 

Sources and acknowledgements

This information has been developed by the RCOG Patient Information Committee. It is based on the RCOG Green-top Clinical Guideline The Management of Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum.