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

Information covered in this leaflet

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.

• What nausea and vomiting of pregnancy is and what hyperemesis gravidarum is
• How it feels to have pregnancy sickness
• What it means for your baby
• What you can do to help if you have pregnancy sickness
• When you should seek medical help and what will happen if you do
• About anti-sickness medication you may be offered

See full glossary of medical terms.

What is nausea and vomiting of pregnancy?

Nausea and vomiting is a symptom of pregnancy and affects most women to some degree. It begins early in pregnancy, most commonly between the 4th and 7th week. It usually settles by 12–14 weeks, 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 pregnancy hormones but it is unclear 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).

It is important that other causes of vomiting are considered and looked into, particularly if you are unwell, have pain in your tummy or your vomiting only starts after 10 weeks of pregnancy. Possible other causes include gastritis (inflammation of the stomach), a kidney infection, appendicitis or gastroenteritis.

What is hyperemesis gravidarum?

If the nausea and vomiting becomes so severe that it leads to dehydration and significant weight loss, it is known as hyperemesis gravidarum. It may affect 1 to 3 in 100 pregnant women. 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.

In severe cases, vomiting can last up to 20 weeks. Occasionally, it can last until the end of pregnancy.

How will it make me feel?

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 ability to care for your family. 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 persistently feel down then you should speak to your healthcare professional.

Will it harm my baby?

There is no evidence that nausea and vomiting has a harmful effect on your baby. In fact, you have a slightly lower risk of miscarriage.

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

What can I do to help?

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

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

Some women find eating or drinking ginger products helps. However, these may sometimes irritate your stomach. Complementary therapies such as acupressure or acupuncture may also be helpful.

If your symptoms do not settle or if they prevent you doing your day-to-day activities, see your GP, who will prescribe anti-sickness medication. This is safe to take in pregnancy.

What if my symptoms do not settle with these measures?

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.

What happens on the assessment unit?

You will have 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
  • you have any other symptoms
  • you have had this in a previous pregnancy
• a check of your general health including your temperature, pulse, respiratory rate and blood pressure; you will have your weight measured and an assessment of whether you are dehydrated
• urine tests
• blood tests
• an ultrasound scan. This is to check how many weeks pregnant you are. It will also check for twins and rule out a molar pregnancy.

If you are able to tolerate some fluids 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 given anti- sickness medication. Many women feel much better after this and are able to go home.

Will I need to be admitted to hospital?

Admission to hospital may be advised if you:

• are dehydrated; having ketones in your urine is a sign of dehydration
• have severe vomiting and are unable to tolerate any fluids
• have abnormal blood tests
• have lost weight
• have a medical condition such as a heart or kidney problem or diabetes.

What happens in hospital?

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

Each day your fluid intake and how much urine you are passing will be recorded. Your temperature, blood pressure, pulse, respiratory rate and weight will also be recorded.

You should be offered:

• anti-sickness medication and a B vitamin called thiamine; both of these can be given through the drip in your arm if you are unable to keep tablets down
• special stockings (graduated elastic compression stockings) to help prevent blood clots
• heparin injections (to thin your blood). Pregnant women are at increased risk of developing blood clots in their legs, called deep vein thrombosis (DVT) or in their lungs (called pulmonary embolism). Being dehydrated and not being mobile increases this risk further. Heparin injections reduce this risk. You will be advised to continue these until you leave hospital and sometimes for longer. For further information, see the RCOG patient information Reducing the risk of venousthrombosis in pregnancy and after birth.

If you are taking iron medication, this will be stopped 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.

What anti-sickness medication will I be offered?

There are a variety of anti-sickness medicines that you may be offered. Not all of the medicines listed below are licensed for use in pregnancy, but there is no evidence that they are harmful to your baby. It is worth considering taking them if other measures have not helped.

• Cyclizine is the medication that is usually given first. It can be taken in tablet form or by an injection. Prochlorperazine and metoclopramide can be tried if cyclizine has not worked. All three of these medications are considered to be safe in pregnancy.
• Ondansetron is another medication that may be prescribed for nausea and vomiting and can be taken by mouth or by injection.
• Corticosteroids may be considered if:
  • you are still suffering from hyperemesis gravidarum despite fluids being given through a drip
  • the above anti-sickness medication has not helped
  • you have lost a lot of weight.

Corticosteroids are successful in many women where all other measures have failed. Most women will be able to stop corticosteroids by 18–20 weeks but 1 in 5 women will need to continue them at a low dose for the rest of the pregnancy. Only a tiny amount of the corticosteroids used to treat hyperemesis gravidarum passes from you to your baby and they are generally considered safe for use in pregnancy. 

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.

After discharge

You will be given anti-sickness tablets to take home. If you feel better, you can cut down the number of tablets. If your vomiting gets worse, stop eating 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.

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.

Further information

NHS Choices: Nausea and morning sickness (www.nhs.uk/conditions/pregnancy-and-baby/pages/morning-sickness-nausea.aspx)

Pregnancy Sickness Support: www.pregnancysicknesssupport.org.uk

For further information on molar pregnancy, see the RCOG patient information Gestational trophoblastic disease.

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.

This leaflet was reviewed before publication by women attending Birmingham Women’s Hospital, by the RCOG Women’s Network and by the RCOG Women’s Voices Involvement Panel.