Hyperemesis Gravidarum and nausea and vomiting in pregnancy – What health professionals need to know

Nausea and Vomiting in Pregnancy (NVP) and Hyperemesis Gravidarum (HG) are common, but underdiagnosed, conditions in pregnancy. They affect 70-80% of women to varying extents and while they are commonly presumed to only occur in the first trimester they often extend well into pregnancy and through to delivery.  

What is the difference between HG and NVP?

NVP is the milder of the two and is generally able to be controlled by lifestyle management and medication use. HG is the severe form and is characterised by unrelenting nausea and/or vomiting that prevents the sufferer from eating and drinking as normal. It causes chronic dehydration and malnutrition and can lead to excessive weight loss. It is the leading cause of hospitalisation in early pregnancy, and, second to premature labour, is the leading cause of hospitalisation during pregnancy overall.  

SOMANZ Proposed Definitions 

The following information has been collected from the Society of Obstetric Medicine of Australia and New Zealand’s Guideline for the Management of Nausea and Vomiting in Pregnancy and Hyperemesis Gravidarum and the International Collaboration for Hyperemesis Gravidarum Research, a working group of patient organisations, researchers and practicing clinicians focussed on furthering research into pregnancy sickness.

Nausea and vomiting of pregnancy: Nausea, vomiting and/or dry retching caused by pregnancy, with symptoms commencing in the first trimester without an alternate diagnosis.  Hyperemesis Gravidarum: Nausea and/or vomiting caused by pregnancy leading to a significant reduction of oral intake and weight loss of at least 5% compared with pre-pregnancy, with or without dehydration and/or electrolyte abnormalities. By definition, this condition is considered severe. 

If sufferers do not receive aggressive, consistent, compassionate and ongoing care they are at risk of the following complications:   

  • Loss of greater than 5% of pre-pregnancy body weight (usually over 10%) 
  • Dehydration and production of ketones* 
  • Nutritional deficiencies 
  • Metabolic imbalances 
  • Severe fatigue and debility 
  • Depression/anxiety and trauma 
  • Premature labour/delivery 
  • Adverse foetal outcomes 

*Ketones are NOT always produced during HG thus ketones are not a required criteria for a diagnosis of HG.) 

While Morning Sickness is a normal, and often welcome, sign of early pregnancy NVP and HG are not normal. Treatment and support should not be withheld or delayed in the hopes that the conditions will simply resolve themselves at 12-weeks gestation. Delaying treatment leads to significantly worse outcomes for the sufferer and developing foetus and increases suffering unnecessarily

~ Caitlin Kay-Smith Founder, Hyperemesis Australia 


As with most chronic illnesses, there is a spectrum of symptoms that may or may not be present in someone suffering from NVP or HG. Symptoms usually begin in the first trimester at about 6-8 weeks gestation, typically peaking at about 9-weeks and settling about 14-weeks for NVP; HG commonly persists until 21-weeks and for some, it will continue throughout the pregnancy until delivery. Most commonly sufferers will be experiencing one or more of these as a result of the nausea and/or vomiting. 

  • Loss of 5% (or more) of pre-pregnancy weight 
  • Dehydration 
  • Constipation 
  • Nutritional disorders, such as vitamin B1 (thiamine) deficiency, vitamin B6 (pyridoxine) deficiency or vitamin B12 (cobalamin) deficiency 
  • Metabolic imbalances such as metabolic ketoacidosis or thyrotoxicosis 
  • Headaches or migraines 
  • Aversions to food (including the sight or smell) 
  • Excessive salivation 
  • Exhaustion 
  • Low blood pressure 
  • Disorientation 
  • Dizziness 
  • Raised pulse 


All women should be asked about NVP at each visit between 4 and 16 weeks and if present, severity should be assessed by PUQE-24 score, measurement of weight and hydration status. For more information on what further investigations should be conducted please consult the full SOMANZ Guidelines available here. NVP is so common in early pregnancy that all maternity focussed care providers should be equipped to care for any woman with mild-moderate symptoms (a PUQE-24 score of 12 or less).   Given that many women expect to be unwell in the first trimester, they may turn to their local pharmacist for advice rather than speaking to their doctor or midwife about it. For this reason, pharmacists and their staff are a vital source of support of information for women.   There are two diagnostic tests that can determine the severity of these conditions in sufferers. The Society of Obstetric Medicine of Australia and New Zealand’s Guideline for the Management of Nausea and Vomiting in Pregnancy and Hyperemesis Gravidarum recommends using the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE-24) test over a 24-hour period. The resulting score will determine whether her condition is mild, moderate or severe and will inform the course of treatment that is appropriate. You can download a printable version of the PUQE-24 questionnaire below. 

View PUQE Scale here

HG and perinatal mental health 

Research has found that having severe morning sickness increases the risk of depression both during and after pregnancy. In fact, one study found that nearly half of women with HG suffered antenatal depression (depression during pregnancy) and nearly 30 per cent had postnatal depression. Some women also reported thoughts of self-harm.  Many women describe feeling miserable that their pregnancy hasn’t been the way they expected it to be and worried about how they’ll cope with a new baby after nine months of ill-health and exhaustion. 


When it comes to treating women with severe NVP or HG (a PUQE-24 score of 13 or above) assessment and care should be undertaken by clinicians with experience with these conditions.

If a specialist of this nature is not available consideration should be given to referring the woman on to someone else, or seeking help via telemedicine. Regardless of who is treating the woman and in what setting, the lead clinician needs to have a clearly communicated and well-documented plan for ongoing management. This allows both the patient and other care providers to understand the nature of the condition, the options available to them for increasing treatment as required and the nature of arrangements for ongoing care.  

For more information on providing care for women with NVP or HG please consult the full SOMANZ Guidelines available here. 

Our recommendations are based on the Society of Obstetric Medicine of Australia and New Zealand Guideline For Management Of Nausea And Vomiting Of Pregnancy And Hyperemesis Gravidarum. 

Many people are hesitant, or even resistant, to taking medication while pregnant. While there are risks associated with many of the recommended medications, these need to be weighed against the risks of leaving symptoms untreated.   Mild to moderate NVP can often be managed without the need for pharmacological intervention. In more severe cases, however, where symptoms are impacting a sufferers ability to eat and/or drink and weight loss is occurring the need for treatment increases.

While concerns around medication use in pregnancy are valid, failing to treat NVP or HG can do more harm than any medication.   The treatments listed below are recommended by the SOMANZ Guidelines for Management of Nausea and Vomiting in Pregnancy and Hyperemesis Gravidarum.

Increasingly, evidence shows the potentially harmful effects of malnutrition and dehydration during pregnancy, including the first trimester. Malnutrition in early pregnancy has been found to have lifelong cardiometabolic consequences for the offspring. Not treating a woman effectively enough to ensure she is able to eat and drink is riskier than leaving her untreated.  

Additionally, the physical and psychological effects of profound and prolonged nausea and/or vomiting should not be underestimated and quality of life should be a factor in decision making about treatments. A recent systematic review of qualitative evidence found that even moderate NVP could have a seriously detrimental effect on sufferer’s lives and mental health.

~ Caitlin Kay-Smith, Founder, Hyperemesis Australia

Treatment Plans

According to the SOMANZ Guidelines any plan for the holistic management of NVP and HG must include:  

  • Interventions to reduce nausea, retching and vomiting  
  • Management of associated gastric dysmotility ie. gastroesophageal reflux and constipation  
  • Maintenance of hydration, fluid and electrolyte replacement  
  • Maintenance of adequate nutrition including the provision of vitamin supplements where required  
  • Psychosocial support  
  • Monitoring and prevention of side effects and adverse pregnancy and fetal outcomes  

And the following considerations for treatment choices in NVP and HG should be made:  

  • Establish reasonable targets for the treatment plan and manage patient expectation ie. aim for the ability to eat and drink adequately without necessarily complete resolution of NVP  
  • Discontinue prenatal multivitamins if they are contributing to symptoms. Many sufferers report an improvement in symptoms after discontinuation of prenatal multivitamins that include iron. The two critical micronutrients which should be continued, if possible, are iodine (150 mcg per day) and folate (at least 400 mcg per day)  
  • The timing of taking medications should take into account the pattern of symptoms over a 24 hour period. Symptoms often fluctuate during the day and night and therapy should reflect these individual differences. Using the PUQE-24 or HELP Scores can help you track and establish patterns, see our previous resource on Diagnosis + Assessment 
  • The choice of antiemetic should be individualised, based on the sufferer’s symptoms, previous response to treatment and potential side effects:  
  • If an antiemetic is ineffective at maximal dose, discontinue before commencing an alternate agent  
  • If an antiemetic is partially effective, optimise dosage and timing, and only add additional agents after maximal doses of the first agent have been trialled  
  • Oral therapy is usually commenced first and parenteral or subcutaneous treatment reserved for severe cases 
  • Written instructions should be given regarding titrating therapy (up and down) as symptoms fluctuate, deteriorate or improve  
  • Regular review of therapy is required in all cases 

Medications for the treatment of NVP and HG Treatment of NVP and HG may require a range of agents including:  

  • Antiemetics: vitamin and prescribed  
  • Acid suppression  
  • Stool softeners  
  • Steroids  
  • Other-supplements  

It is important to remember that pharmacological treatment for NVP and HG is only one part of the holistic management of a patient’s condition. Other elements will include, where appropriate, non-drug measures, psychosocial support and ongoing obstetric/midwifery care.  

Almost all pharmacological treatment is “off-license” and based on historical experience with the limited amount of high-quality research data described in small trials or systematic reviews or meta-analyses. In all cases, a rational assessment of maternal and fetal risk, particularly teratogenesis, needs to be determined based on the patient’s circumstances. Read the most recent and relevant research available here dowornload the full SOMANZ guideline.

Download SOMANZ guideline

Intravenous Fluid Replacement

Sufferers will often delay seeking treatment for NVP and HG if they don’t realise their symptoms have gone beyond what can be reasonably expected from first-trimester sickness. This means that it may be necessary to accelerate treatment to correct the damage of weeks of untreated illness. IV fluids and electrolyte replacement play an important role in both reversing dehydration and managing NVP and HG long term. They have been shown to reduce vomiting and are, therefore, a valuable part of any treatment plan.  

Read more about IV fluids

Nutritional Therapies

If the sufferer does not respond to the recommended management interventions, they should be assessed by a dietitian to consider commencing short-term enteral feeding. Small studies have shown enteral feeding is safe and effective in temporarily aiding fetal and maternal nutrition in severe HG. Undertake a detailed nutritional assessment to determine the feeding regimen required. 

Read more about nutritional therapies

Therapeutic Abortions

Research suggests that as many as 10% of women with HG will terminate their pregnancy due to the severity of their symptoms. Termination should only be discussed when all other treatment avenues have been exhausted with little efficacy. We want to avoid the termination of a wanted pregnancy due to complications associated with HG. No patient should have to end a pregnancy because their symptoms are too severe for them to cope with, so abortion should be the absolute last resort as a treatment for HG.

How to help those in your care

Patient Comfort 

Nausea and Vomiting in Pregnancy and in particular, Hyperemesis Gravidarum is a challenge for both the sufferers and the healthcare professionals caring for them. Below is some information about how you can help sufferers with this debilitating and devastating condition both in the community and as in-patients on the ward. 

  • Reduce sensory stimuli and triggers as far as possible – in particular odours from food, perfumes, coffee and so on but also lighting and noise levels, motion and general interruptions to rest. Sufferers admitted to the hospital with Hyperemesis Gravidarum should be in a side room so as to reduce sensory stimulation 
  • Listen to them: loneliness and isolation may well be a major part of their distress 
  • Watch for signs of psychological illness as a result of the condition and refer for assessment as appropriate. Depression is not a cause of Hyperemesis but can become a symptom of it 
  • If possible, refer to a physiotherapist to minimise the effects of atrophy from prolonged bed rest 
  • Measure legs and prescribe TED Stockings to reduce the risk of Deep Vein Thrombosis 
  • Ask for permission before discussing food and before mentioning food names in case it triggers nausea 
  • Ascertain the level of sickness by asking what foods and drinks have been tried, what has helped/what has not and taking a thorough history. Encourage them to fill in a daily diary to look for a pattern 
  • Be careful if recommending “morning sickness cures” to an HG sufferer; they will have been told innumerable times to try crackers and ginger. It may undermine confidence in healthcare professionals as well as adding to their feelings of isolation. Many sufferers of Hyperemesis report that the suggestion of ginger instils feelings of anger and hopelessness 
  • Do not challenge what they are or are not eating/drinking; anything is better than nothing (within current recommended safe-food guidelines) 
  • Refer them to this website for information on eating and drinking and coping strategies as well as for support for both them and their loved ones 
  • Watch for signs of dehydration (Ketones are not a sign of dehydration) 
  • Alleviate any guilt and reassure them if they have been unable to take prenatal vitamins. Medication is necessary for severe Hyperemesis Gravidarum and sufferers should be reassured of the need for safe, effective treatment 
  • Remind them to take the pregnancy a day at a time and that the HG will end, even if that is not until delivery 
  • Remember that pregnancy sickness is not always a ‘good sign’. There are many cases of sufferers whose HG has continued despite later discovering that the foetus died weeks earlier. Furthermore, remember that many suffer from HG so badly that they consider termination as their only remaining option 
  • Encourage appropriate medication 
  • Those with prolonged illness and inadequate medical care – e.g., those with greater than 10 per cent loss of pre-pregnancy body weight or those who fail to gain weight for two consecutive trimesters – are at increased risk of serious complications such as pre-eclampsia and pre-term labour. A referral should be made to an obstetrician or assessment unit to check for signs of Intra Uterine Growth Retardation 
  • Remember that recovering from HG takes time and that there may be a long-term impact on both sufferer and baby.

This information has been developed in partnership with Hyperemesis Australia.

Hyperemesis Australia is a nation-wide charitable organisation focussed on supporting sufferers of pregnancy sickness, their families and healthcare professionals.  Hyperemesis Australia is committed to raising awareness of both Nausea and Vomiting in Pregnancy (NVP) and Hyperemesis Gravidarum (HG) within the public, media and health care professionals as well as fostering understanding of the conditions and their impacts.

Visit the website here