Treating nausea and vomiting in 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.

Ondansetron

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 www.uktis.org.