Medications & treatments
This information is intended to inform, raise awareness and empower healthcare professionals to treat the symptoms of HG. The responsibility for any medical treatment rests with the prescriber.
Are anti-emetics safe to prescribe in pregnancy?
According to the RCOG guidelines, the anti emetics included in the 3 lines of treatment “can and should be used with confidence in primary and secondary care to manage women’s symptoms.” (Nelson-Piercey, C. 2024)
Further information about the efficacy and safety of medications is provided in the guidelines so clinicians can feel confident that they are based on the best available evidence at the time of publication.
More information for Healthcare Professionals about medications and their safety during pregnancy can be found at the UK Teratology website.
Early recognition and management of NVP could have a profound effect on women’s health and quality of life during pregnancy.
What is the definition of HG?
Did you know in 2021 an international definition of hyperemesis gravidarum was proposed and agreed to? It is called the Windsor Definition.
This definition states that there are 4 criteria which must all be met to diagnose HG:
- Symptoms start before 16 weeks gestation;
- Nause and vomiting, one of which is severe;
- Inability to eat and/or drink normally;
- Symptoms strongly limit daily activities
The Windsor Definition is already being used clinically across the UK following its inclusion in the updated RCOG guidelines 2024.
It is hoped it will also help clinical studies to achieve more uniformity, and ultimately increase the value of evidence much of which was hampered by a lack of international definition. (O’Donnell et al, 2016 and Boelig et al, 2016)
Ginger and pregnancy sickness
PSS conducted a survey of over 500 women’s experience of being offered and taking ginger for hyperemesis gravidarum which found that Ginger is ineffective for hyperemesis gravidarum, and causes harm.
Not only does ginger produce unpleasant side effects which often exacerbate symptoms but the psychological impact of being told to take ginger repeatedly was found to be detrimental to well-being.
Where healthcare professionals recommended ginger to women with HG, trust and confidence in the professional was eroded and women were left feeling dismissed and unheard.
The Aetiology of Hyperemesis Gravidarum
What medications and treatments can be prescribed?
Hyperemesis Gravidarum is a serious complication of pregnancy and it is essential that sufferers are offered timely and effective treatment. The RCOG Greentop Guidelines include a treatment ladder that outlines the various medications that are recommended for use in HG pregnancies alongside intravenous fluid therapy and PPIs.
Medication Information
Currently, there is only one anti-emetic licenced for use in pregnancy in the UK which is called Xonvea. It is a combination of Doxylamine Succinate and Pyridoxine Hydrochloride which is available as a delayed-release tablet.
It is not yet available everywhere across the UK and as it’s only available in oral form, it is a first-line medication and alone, may not be sufficient to manage the symptoms of HG.
PSS are campaigning for Xonvea to be included on all formularies in the UK to avoid the current postcode lottery. If you want support to add this to your formulary please contact us.
Alongside IV Fluids, 3 lines of anti-emetic medications are outlined in the RCOG Guidelines for the management of NVP in Pregnancy and HG.
The Principles of treatment of HG are:
Rehydrate – Balance electrolytes – Maintain with antiemetics – Manage expectations
Any information provided here is based on RCOG Guidelines 2024 and, as with all clinical decisions, medications should be considered using a Risks v Benefits analysis and in partnership with the patient.
FIRST LINE MEDICATIONS
According to the RCOG guidelines, “Clinicians should use antiemetics with which they are familiar and should use drugs from different classes if the first drug is not effective or only partially effective.”
Antihistamines:
Promethazine is also known as Phenergan and Avomine.
Side effects – Antihistamines can cause drowsiness which can be problematic to some patients. Side effects can ease after a week or two in some cases.
Phenothiazines:
Prochlorperazine (also known as Stematil and Buccastem) is available in tablet form and as a buccal that dissolves on the gum.
Side effects – include drowsiness, restlessness and occasional extra pyramidal effects (Such as tremor, slurred speech, anxiety, distress and others).
SECOND LINE MEDICATIONS
According to the RCOG Guidelines, “Because there are no clear data supporting increased efficacy of one class of antiemetic over others the suggested step wise approach…is based predominantly on safety data”
Dopamine Antagonists
The RCOG Greentop Guidelines 2024 state Metoclopramide is safe and effective and can be used alone or in combination with other antiemetics.
Side Effects: Risk of extrapyramidal symptoms for the mother (such as muscle twitching, spasms, tremors and dizziness).
These symptoms will generally appear quickly so if they haven’t appeared in the first 5 days it’s unlikely that they will develop after this point. The risk is higher (but still rare) when receiving metoclopramide via IV.
In spite of the EMA recommendations, “it [metoclopramide] can be prescribed for more than five days in those women who gain symptomatic relief from it.” Nelson-Piercey, C (2024)
The BNF Notes that the 5-day rule restriction does not apply to unlicensed uses (such as treating pregnancy sickness).
Ondansetron
Ondansetron (also know as Zofran) is a selective 5-HT3 serotonin antagonist and is now widely used to treat nausea and vomiting in pregnancy.
The RCOG Greentop Guidelines 2024 state Ondansetron is safe and effective. Its use as a second-line antiemetic should not be discouraged if first line antiemetics are ineffective.
Women can be reassured regarding a very small increase in the absolute risk of orofacial clefting with ondansetron use in the first trimester, which should be balanced with the risks of poorly managed HG.
There is some reluctance to prescribe Ondansetron in the first trimester, however research by Huybrechts et al (2018) found that there is no link to heart defects and an extremely minimal ‘associated risk’ (not direct cause) to cleft lip/palate when taken in the first 10 weeks of pregnancy.
To put this into perspective, in a typical pregnancy, the base line risk of cleft lip/palate is 11 in every 10,000 babies. With ondansetron use there was found to be an extra 3 babies in every 10,000 so the absolute risk is tiny.
THIRD LINE MEDICATIONS
Steroids
- Hydrocortisone 100 mg twice daily IV until clinical improvement occurs.
- Convert to prednisolone 40–50 mg daily PO, with the dose gradually tapered (by 5-10 mg per week) until the lowest maintenance dose that controls the symptoms is reached
- Gestational diabetes – blood sugar monitoring should be performed if taking steroids long term (>4 weeks)
- Increased risk of infection e.g. urinary tract infections
If a pregnant person’s hyperemesis is so severe that they are considering termination of the pregnancy, then steroids should be considered (personal medical history and circumstances dependant).
INTRAVENOUS FLUIDS
Intravenous fluids (sodium chloride 0.9%) are given to correct dehydration and metabolic disturbances, alongside anti-emetics when oral medications cannot be tolerated.
Signs and symptoms of dehydration should be assessed when considering the need for IV fluids rather than outdated Ketone analysis which has been rejected as a diagnostic tool for HG in the RCOG Guidelines 2024.
IV fluid replacement remains an effective treatment for dehydration, which actually can cause nausea and vomiting. Women often feel temporary but effective relief from a few bags of IV fluids.
TERMINATION FOR MEDICAL REASONS (TFMR)
Over 50% of people diagnosed with HG have considered a termination.
Research suggests between 5-10% terminate a pregnancy due to hyperemesis. Often this is due to inadequate treatment of symptoms and/or a lack of support and understanding from healthcare professionals, employers, and their support network.
In partnership with the British Pregnancy Advisory Service (BPAS) Pregnancy Sickness Support examined the main drivers for terminations in pregnancies complicated by HG to examine what more can be done to improve care for people in this situation and better support for their choice.
In this research, many women who terminated their pregnancies reported feeling that their healthcare professionals (HCPs) lacked compassion, with such sentiments being three times more common among them than among those who did not terminate. Additionally, there were numerous accounts highlighting a distressing dilemma where they felt their only options were either abortion or suicide.
PSS advocate for all options to be explored before a termination is offered while supporting women’s right to choose.
Please signpost any patients to our Support team for additional support or for Peer Support.
If you have a patient that has terminated a pregnancy please signpost them to our HG & Loss page for more support including our Therapeutic Termination Support Group.
UNDERSTANDING SAFETY AND CONFIDENCE TO PRESCRIBE
At Pregnancy Sickness Support we believe in making an informed decision based on research. There is no evidence to show that anti-sickness medications cause harm.
As with all medication use, not just in pregnancy, but throughout life, decisions should be collaborative and always based on the balance of risks and benefits.
There are medications that you can prescribe which have been extensively researched and used for many years (some over 50).
It’s also important to consider the effects to mother and baby from unmanaged dehydration and malnutrition. The risk to mother and baby of untreated HG is something that women should be made aware of to enable them to make an informed decision on medications and treatments and undertake a risk benefit analysis.
The medications that can be prescribed are often off-license; the truth is there are very few licenced medications in pregnancy, even self-administering medications such as paracetamol and aspirin have no licence.
Please contact out support team if you want to discuss any of the information on this page.
ADVOCATING FOR PATIENTS IN YOUR CARE
The care that women and pregnant people receive during their HG pregnancy can vary hugely, with some healthcare professionals giving excellent advice and managing their symptoms well, while others can be dismissive and unhelpful even refusing to prescribe ongoing anti emetics.
It makes a huge difference to know that there is a trusted healthcare professional to turn to if care isn’t good enough.
You can be that safe space that sufferers come to so they can discuss any issues or concerns about their care. If you can then advocate on their behalf where appropriate, this would be a huge catalyst for change in HG pathways and care.
Additionally, please signpost anyone you are treating for HG towards Pregnancy Sickness Support. Our fantastic Support Services including Peer Support can be an life line for sufferers providing ongoing emotional support and guidance throughout pregnancy.
“Measuring for ketones would have indicated that I was not unwell even when I was extremely dehydrated. Thankfully I was generally assessed and given appropriate treatment.”
Anonymous