Hyperemesis Gravidarum (HG)

Hyperemesis Gravidarum (HG) is a severe form of Nausea and Vomiting of Pregnancy (NVP). It affects around 1-1.5% of all pregnant women. The cause (or causes) of HG remain unknown and there is no standard definition for the point at which NVP and HG meet, and no specific test that can diagnose it. However the most generally quoted symptoms leading to the diagnosis of HG include near constant nausea and frequent vomiting that is affecting your ability to function normally, weight-loss of more than 5%, dehydration, and malnutrition. What we do know about the causes of HG is that for many women there is a strong genetic element (women whose mother or sister suffered are more likely to get it themselves) and that it is not a psychological condition. Nothing you do or don’t do will cause HG to occur and it is not your fault that you are experiencing it.

Hyperemesis Gravidarum Key Information

What are the symptoms of HG?

In addition to the symptoms described above, HG typically presents itself with severe and persistent nausea and/or vomiting, leading to weakness and exhaustion. Some women vomit multiple times every day, others may vomit less frequently but suffer from nausea and dry retching that affects their ability to function. If nausea and/or vomiting is so severe that it affects your ability to carry out normal tasks such as eating, drinking, personal hygiene, or your ability to work or care for older children then it is worth contacting your GP or midwife.

In addition to feeling and being sick women with HG also can experience headaches, a very heightened and warped sense of smell, excessive saliva which is difficult to swallow, constipation and a number of other symptoms.

What are the risks associated with HG?

Since the introduction of IV hydration, HG is rarely the life-threatening illness it once was. However prolonged dehydration and malnutrition can lead to various health risks including vitamin deficiencies and electrolyte imbalances which need to be monitored and managed.

While recent research has shown that if HG is not effectively managed there may be increased risks to the baby, such as small for gestational weight gain and pre-term birth, it is important to remember that if treatment is sought and symptoms brought under control the risks to the baby are very low.

Increasingly research is showing that it is the malnutrition in early pregnancy that leads to complications, rather than the actual nausea and vomiting, so it’s important to seek help if sickness is stopping you eating.

What treatment options are available?

If a woman is becoming dehydrated because she cannot keep fluid down then it is important that she receive Intravenous fluid replacement (a drip). This is usually done in hospital but increasingly areas are offering outpatient rehydration which allows women to receive fluids during the day and return home at night.

There are a number of anti-sickness drugs which are used to treat NVP and HG. One, called Xonvea, is licensed in the UK. If that doesn’t work though there are lots of others which are not licensed for use in pregnancy but have been used for many years and no harmful effects for the baby have been found.

Many women can feel guilty about taking medication in pregnancy as there are long held beliefs that drugs should be avoided and may harm the baby but with a serious condition such as HG it is important to remember that NOT treating symptoms effectively can carry risk and many thousands of pregnant women have taken medication without harm to the baby.

Unfortunately many women suffering from HG encounter healthcare providers with limited knowledge or experience of treating HG and who may misdiagnose the symptoms as normal. This is often exacerbated by the difficulty in describing the severity of symptoms in a clear way, and so it can be helpful to keep a thorough record of symptoms.

Can alternative therapies help?

While many women who experience regular “morning sickness” may find that Complementary and Alternative Medicines (CAM) may help with symptom management, for women with HG it is important that conventional treatment is not delayed by exploration of CAM. The national helpline run by Pregnancy Sickness Support speak to hundreds of women every year with hyperemesis, Karen Lodge, who answers the helpline says “Almost everyone I speak to has already tried ginger, acupressure, aromatherapy and the various other self-help techniques available before they even visit their GP or see their midwife. Information about self-help and CAM options are widely available and therefore healthcare professionals can confidently assume that women already know about them”. While there has been some evidence for ginger to ease nausea and vomiting a recent large scale survey of women’s experience of ginger for HG found that in 50% of women it actually made symptoms worse and cause pain and discomfort. Furthermore they found that when healthcare professionals suggested it to women who had a diagnosis of HG it had a profoundly negative impact on their mental wellbeing.

What role can midwives play?

As the symptoms of HG typically begin during the first trimester, a woman suffering from it is likely to have had considerable contact with her GP before ever meeting her midwife at the booking appointment. But the midwifery team involved in her care can still play a key role in her treatment.

If the woman is admitted to hospital, it is important to offer empathy and understanding. HG is far more than typical NVP symptoms and the woman may be feeling totally isolated and alone. For many women this may be their first bout of serious ill health in their lives and at a time that they were hoping to be joyous and exciting. Many women mention the lack of care given and how they have been expected to ‘pull themselves together’ or settle into the hospital routine on a busy ward even though the various different stimuli may all act as triggers for the sickness. A recent literature review found that the historic stigma of HG caused by notions of psychodynamic aetiology persists today and negatively impacts the care they receive. That said, awareness of HG is improving at a phenomenal speed and services such as HG Day Units are opening up across the UK with women giving excellent feedback on the care they are receiving in many areas.

Whether in a hospital or clinic setting, the midwife can offer welcome knowledge and understanding on the severity of the sickness experienced. One of the main things to note is that the term “morning sickness” is both inaccurate and trivialises the condition. Many women with NVP and HG experience at least two episodes per day and some mention that the symptoms are worse later in the day when tiredness affects them. Therefore, asking about a woman’s specific symptoms and noting how much they are affecting her life can give a clear indication of the help she needs. The Motherisk Program in Canada created a Pregnancy Unique Quantification of Emesis (PUQE) scale which asks women to monitor how many hours they feel ill, how often they actually vomit, and how often they have dry-retched over a 24 hour period to evaluate the severity of their symptoms. This could be a useful tool for midwives to adopt, particularly for NVP, however it is important to note that it may be inaccurate or insensitive at the HG end of the spectrum.

It may also help the woman to maintain a diary of symptoms. This may help her determine when the symptoms are at their minimum and hence the better time to try food and drink. A diary can downloaded from the Pregnancy Sickness Support website and there is a page about HG in the Mums section of the MAMA Academy site which includes information and coping strategies.

It is important to remember that such severe symptoms are often unresponsive to the normal suggestions for NVP. Advising a woman with HG to ‘eat little and often’, ‘try ginger’ or ‘eat a dry cracker before getting out of bed’ will only upset her if she has been unable to keep even the smallest amount of liquid down each day. Instead it is best to ask her what she can tolerate, check before mentioning food (in case this is a trigger for her sickness) and advise her to eat and drink whatever she can tolerate, whenever she can tolerate it. However, women suffering from NVP and HG also often have a greater sensitivity to smells, and it may help women to avoid odours in the house, especially those involved in the preparation of food.

Knowledge of HG and the treatment options available would be highly valuable in the care of women with severe symptoms and may help reassure them that treatment is available and that they need not suffer in silence. This is where the midwife could play a vital role, providing the information a woman needs to make choices that are right for her. Advocacy is a key role of the midwife for all of her women and this can be particularly important for women with HG who may find advocating for themselves difficult or almost impossible.

Unlike the more typical NVP, women suffering from HG will often experience symptoms throughout the second and even third trimesters, often only gaining relief once the baby is born. As contact with the midwifery team increases as the pregnancy progresses, they can offer continuity of care by always asking about the symptoms experienced, both physical and emotional.

Finally it is important to note that many women suffering from severe NVP never gain a diagnosis of HG and struggle to gain appropriate care and treatment despite many visits to the GP and/or midwife. In fact Jarvis notes that approximately 35% of pregnant women will suffer from symptoms that are of clinical relevance. Therefore there is a clear need to offer support and guidance to any woman suffering from unusually severe symptoms as they may feel invalidated through the lack of diagnosis.

What are the NICE guidelines for HG?

The NICE guidelines only make recommendations for NVP and include ginger, P6 acupressure and antihistamines for NVP, but make no specific recommendations for HG. However, they do provide a Clinical Knowledge Summary which outlines the various drug therapies which is based on the widely accepted Javis and Nelson-Pericy Paper.

The NICE guidelines specifically states:

“Women, their partners and their families should always be treated with kindness, respect and dignity. The views, beliefs and values of the woman, her partner and her family in relation to her care and that of her baby should be sought and respected at all times.

“Women should have the opportunity to make informed decisions about their care and treatment, in partnership with their healthcare professionals […]Good communication between healthcare professionals and women is essential. It should be supported by evidence-based, written information tailored to the woman’s needs […] Every opportunity should be taken to provide the woman and her partner or other relevant family members with the information and support they need.”

What other guidelines are available?

In 2016 the Royal College of Obstetricians and Gynaecologists launched their first edition of Greentop Guidelines for NVP and HG which have helped to standardise and improve access to treatment across the UK. The guidelines have been developed in conjunction with the patient advocacy charity Pregnancy Sickness Support (PSS) and have been praised for having the patients voice ingrained throughout the guideline. They are due to be updated this year to incorporate recent research. Unfortunately not all hospitals have adopted these guidelines and many have their own area specific guidelines which rarely include the patient voice and often restrict access to treatment with criteria such as having to have ketones in your urine to access treatment, which is not supported by evidence and is considered old fashioned and misguided. Hopefully with updated guidelines from the RCOG, more hospitals will adopt them into practice.

What other support can be offered to women?

The UK charity Pregnancy Sickness Support (PSS) has a helpline and webchat which is open Monday to Friday 9am-4.30pm and can offer information and support to women, their partners or family members. The charity also has a 1-2-1 support network of volunteers whom you can be matched with for support as well as a website forum for 24/7 support online.

For posters, leaflets and other display materials for your clinical area please contact the charity via the helpline or website.

With thanks:
In partnership with Pregnancy Sickness Support.

Visit their website which contains a wealth of other information for use by patients, carers and professionals, including reviews of literature.


Last revised: January 2021

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