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Hyperemesis gravidarum (HG)

What are the signs and symptoms of hyperemesis gravidarum (HG)? Here we look at how women can find support and treatment.

In this article we cover the following topics:

What is hyperemesis gravidarum?
What causes hyperemesis gravidarum?
How is hyperemesis gravidarum treated?
Will hyperemesis gravidarum harm my baby?
How you might be feeling

While some experience of sickness in pregnancy is common, one in 100 pregnant women experience excessive nausea and vomiting, which is known as hyperemesis gravidarum (HG). This condition can be debilitating and disruptive to daily life and, in some cases, can require hospital treatment.

What is hyperemesis gravidarum?

HG is a severe form of nausea and vomiting in pregnancy. The clinical definition varies, but generally includes:

  • Difficulty with daily activities.
  • Weight loss of more than 5% of pre-pregnancy body weight, usually over 10%.
  • Dehydration caused by not being able to keep food and fluids down.
  • Ketosis: a condition that results in the build-up of acidic chemicals in the blood and urine (ketones are produced when your body breaks down fat, rather than glucose, for energy).
  • Metabolic imbalances and nutritional deficiencies.

HG usually extends beyond the first trimester and may end by 21 weeks; however, it can last for the entire pregnancy for a few women. Complications of vomiting (e.g. gastric ulcers, oesophageal bleeding, malnutrition, etc.) may also contribute to and worsen ongoing nausea.

What causes hyperemesis gravidarum?

HG is generally thought to be associated with hormonal changes during pregnancy. Unfortunately, the causes are not fully understood and conclusive evidence is not available. New theories and findings emerge every year though, which further underline the fact that this is a complex physiological disease probably caused by multiple factors.

There is some evidence that it runs in families, so if your mum or sister has had HG in a pregnancy, you may be more likely to get it yourself. Other risk factors include pre-existing diabetes, hyperthyroid disorder, depression or psychiatric illness, asthma and gastrointestinal disorders.

Furthermore, if you’ve had HG in a previous pregnancy, you’re more likely to get it in your next pregnancy than women who have never had it before, so it's worth planning in advance.

How is hyperemesis gravidarum treated?

Treating HG is challenging but getting treatment early is important so don’t delay talking to your GP or midwife if you think you might be suffering from it. Preventing and addressing nutritional deficiencies will be a high priority to ensure both mum and baby are safe and healthy.

There are medications that can be used in pregnancy, including the first 12 weeks, to help improve the symptoms of HG. These include anti-sickness (anti-emetic) drugs, vitamins (B6 and B12) and other pharmacological agents or combinations of these. Your GP will be able to advise on whether these are necessary, which is most suitable for you and any possible side-effects. Evidence suggests that the earlier you start treatment under medical care, the more effective it will be.

The HER (Hyperemesis Education and Research) Foundation, which provides support and information on HG, also suggests that a pregnant woman who has not been able to eat should get intravenous (IV) vitamins, especially B complex to avoid Wernicke’s disease. This happens when glucose fluids are given while a person is deficient in B1 or thiamine. As we don’t make thiamine in our body and have to get it from grains and meat, it’s very commonly deficient among women who suffer from HG. Early signs are weakness and depression so it’s often missed. Women suffering from HG could consider taking B1/thiamine to avoid this.

Your GP may need to try different types of medication until you find what works best for you.

If your nausea and vomiting cannot be controlled, you may need to be admitted to hospital. This is so that doctors can assess your condition and give you the right treatment, to protect the health of you and your baby.

Treatment can include intravenous fluids, which are given directly into a vein through a drip. If you have severe vomiting, the anti-sickness drugs may also need to be given via a vein or a muscle.

Will hyperemesis gravidarum harm my baby?

Most studies examining the risks and outcomes for a pregnant woman with nausea and vomiting in pregnancy find that it is unlikely to harm the baby in milder cases. Those with more severe symptoms that lead to prolonged nausea and vomiting and/or severe weight loss are at greatest risk of complications, such as having a premature baby or baby with a low birth weight. The risk increases if medical intervention is inadequate or delayed, which is why it’s so important to seek help and support early.

How you might be feeling

The nausea and vomiting of HG can affect you both emotionally and physically. Malnutrition and vitamin deficiencies may lead to anaemia, and combined with dehydration, treatment could require being in hospital. Severe sickness can also be exhausting and stop you from doing everyday tasks, such as going to work or even getting out of bed. This can make you more likely to feel anxious or depressed.

Many women find it hard to talk openly about feeling anxious or low but it’s really important that you are honest with friends and family, and your midwife or GP. Explain the impact HG is having on your life and how it’s making you feel. You may also find it helpful to talk to other women who have experienced HG and find out how they coped (see link for The HER Foundation below).

Some of the content for this article is taken from The HER Foundation and NHS Choices

Further information

NCT's helpline offers practical and emotional support in all areas of pregnancy, birth and early parenthood: 0300 330 0700. We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.

The HER Foundation has lots of useful information and support on HG

Pregnancy Sickness Support is a UK charity working to improve care, treatment and support for women suffering from Nausea and Vomiting in Pregnancy (NVP) and Hyperemesis Gravidarum (HG)

NHS choices provides information on hyperemesis gravidarum