Treating nausea and vomiting in pregnancy

(Date: September 2019. Version: 2.0)

This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by the UK Health Security Agency (UKHSA) on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.

What is pregnancy sickness?

Nausea and vomiting are commonly experienced in early pregnancy and are often referred to as ‘morning sickness’ but can occur at any time of the day. Most women are affected between week 6 and 16 of pregnancy, but for some, symptoms persist for longer and can even occur throughout pregnancy. A small number of women experience a very severe form of pregnancy sickness called hyperemesis gravidarum and may require hospitalisation and rehydration with intravenous fluids.

What are the treatments for nausea and vomiting in pregnancy?

Women with mild pregnancy sickness can try certain lifestyle changes that may improve symptoms. These include getting plenty of rest/sleep, eating smaller regular meals with high carbohydrate content, eating dry toast or a plain biscuit before getting up in the morning, avoiding fatty food and food with strong odours, and drinking adequate fluids. ‘Home remedies’ for nausea and vomiting, such as ginger and acupressure bands that are designed to help with travel sickness, can also be tried. If you feel you cannot cope with your symptoms you should ask your doctor for advice as several anti-sickness medicines can be prescribed. Please see the sections below for further details.

Promethazine (Phenergan,® Sominex,® Avomine®) and cyclizine

Promethazine and cyclizine are types of antihistamine commonly used to treat nausea and vomiting in pregnancy. Studies on the use in pregnancy of antihistamines in general and of cyclizine and promethazine specifically have not shown that these medicines increase the chance of having a baby with a birth defect. For further information, please see the promethazine bump leaflet.

Xonvea® (doxylamine/pyridoxine)

Xonvea® contains a combination of the antihistamine doxylamine and the vitamin pyridoxine, and became available in England in 2018. It has been widely used for pregnancy sickness in the US and Canada and studies have shown no link with birth defects in the baby. Please read the bump leaflet on use of Xonvea® in pregnancy for more detailed information.

Prochlorperazine (Buccastem,® Stemetil®) chlorpromazine, metoclopramide (Maxolon®) and domperidone (Motilium®)

There is not much pregnancy safety information for prochlorperazine, chlorpromazine, metoclopramide and domperidone, but the scientific information that is available so far does not show that these medicines are harmful to a developing baby.


Although a possible link between ondansetron use in early pregnancy and cleft lip and/or palate in the baby has been suggested, current research suggests that the chance of this occurring is very small. A large, well-designed study found that the vast majority of babies exposed to ondansetron in the womb (at least 998 out of every 1,000) are born without cleft lip and/or palate.

There has also been some evidence that babies exposed to ondansetron may have a higher chance of having a heart defect. However, as a large, well-designed study did not show any link with structural heart disease in the baby, more evidence is still needed.

Women can be seriously affected by severe pregnancy sickness (hyperemesis gravidarum). Without treatment, they are at risk of dehydration and poor mental and physical health. Ondansetron may be offered in these circumstances, in which case their doctor/obstetrician will help them to weigh up the benefits of its use against the possible risks.

Please read the bump leaflet on use of ondansetron in pregnancy for more detailed information.

Corticosteroids (e.g. hydrocortisone, prednisolone)

Corticosteroids are sometimes prescribed for women with hyperemesis gravidarum that has not responded to other treatments. There is no strong evidence that use of corticosteroids in early pregnancy increases the chance of cleft lip and palate or heart defects in the baby. Use in pregnancy also does not appear to increase the chance of the baby having a low birth weight. Some studies have shown that pregnant women taking corticosteroids have a higher chance of preterm delivery. However, it is thought that this is likely caused by the underlying illnesses that steroids are commonly used to treat rather than a direct effect of steroids themselves. Please read the bump leaflet on use of systemic corticosteroids in pregnancy for more detailed information.

Will my baby need extra monitoring during pregnancy?

As part of their routine antenatal care, most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects and to check the baby’s growth.

The need for additional tests or monitoring during pregnancy will largely depend on how unwell the mother is. For example, if you have been diagnosed with hyperemesis gravidarum your obstetrician may recommend closer monitoring of your baby’s growth and well-being. For most anti-sickness treatments, however, no extra monitoring during pregnancy will be necessary.

Who can I talk to if I have questions?

If you have any questions regarding the information in this leaflet please discuss them with your healthcare provider. They can access more detailed medical and scientific information from

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General information 

Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks.  They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.

Medicines use in pregnancy

Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby.  There are, however, some medicines that can harm a baby’s normal development.  How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.

If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.

When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.   

Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.

Disclaimer: This information is not intended to replace the individual care and advice of your health care provider. New information is continually becoming available. Whilst every effort will be made to ensure that this information is accurate and up to date at the time of publication, we cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes following decisions made on the basis of this information. We strongly advise that printouts should NOT be kept for any length of time, or for “future reference” as they can rapidly become out of date.

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