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

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:

• 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.
• medication to reduce the acid in your stomach.
• 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 venous thrombosis in pregnancy and after birth (https://www.rcog.org.uk/for-the-public/browse-our-patient-information/reducing-the-risk-of-venous-thrombosis-in-pregnancy-and-after-birth-patient-information-leaflet/)

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.