Nausea and vomiting in pregnancy and hyperemesis gravidarum

Nausea and vomiting in pregnancy (NVP) affect up to 80% of pregnant women in the UK^​1​. NVP is one of the most common indications for hospital admission in pregnancy, with a typical in-patient admission of three to four days^​2–4​. The financial burden of managing NVP in the UK is significant. It is estimated the management of NVP costs the NHS around £62m annually, owing to the hospital admission, GP visits and ambulance callouts^​1​. One meta-analysis study, published in 2013, revealed that the average global prevalence rate of NVP was 69.4%^​5​. Among the pregnant women in the analysed studies, 32.7% had nausea without vomiting, while 23.5% had NVP continuing into the third trimester^​5​.

The definition of NVP is the symptom of nausea and/or vomiting during pregnancy when onset is prior to 16 weeks of gestation and where there are no other causes^​6​. NVP symptoms usually begin between the 4th and 7th weeks of gestation, with the peak of symptoms appearing in approximately the 9th week. According to the results of a study published in 2024, NVP symptoms are usually resolved by the 20th week in 90% of the affected women^​6​.

Hyperemesis gravidarum (HG) is a severe form of NVP, with an average global prevalence of 1.1%^{​5,7–9​}. It affects the quality of life of pregnant women, especially the ability to eat and drink normally^​6​. Women with HG may become dehydrated, lose weight or require hospital admission when complications arise^​10,11​. After the experience of HG, patients often report the symptoms of anxiety, depression and post-traumatic stress disorder (PTSD)^{​12–14​}. HG may also increase the chance of preterm birth and small-for-gestational-age (SMA) status. There is also some evidence that suggests a small increase in certain long-term adverse health outcomes in the offspring born to women who had HG^{​15–23​}. Examples of these adverse outcomes are neurodevelopment disorders, mental health disorders, attention deficit hyperactivity disorder and autism, overall cancer risk and possibly testicular cancers and neuroblastoma^{​15–23​}. According to a Danish study, published in 2023, HG is associated with an increased risk of neuroblastoma, acute lymphoblastic leukaemia and non-Hodgkin’s lymphoma. The study authors suggested that women with HG should be closely monitored^​16​. 

In a population-based pregnancy cohort study using UK GP data, published 2019, the prevalence of clinically recorded NVP/HG was 9.1%, of which 2.1% of patients were admitted to hospital, 3.4% were treated with antiemetics in primary care only, and 3.6% had only a recorded diagnosis^​24​. 

Aetiology

A systematic review, published in 2019, examined the predictive factors of HG^​23​. The exact pathophysiological mechanism is not known, but the most important risk factors seemed to be Helicobacter pylori infection, genetic predisposition, low body mass index, female embryo, multiple pregnancy, hyperthyroidism, beta-chorionic gonadotropin (β-hCG) and a history of HG in the previous pregnancy^​23​.

Other studies have been undertaken to better understand the aetiology of HG. A genetic origin for HG is supported by the results of familial aggregation studies, twin studies and a genome‐wide associate study^​25,26​.

A genome-wide association study of more than 50,000 participants, published in 2017, linked the gene growth differentiation factor 15 (GDF15) to HG^​27​. There were significant associations with the insulin-like binding factor protein 7 (IGFBP7), the progesterone receptor and the GDF15 receptor GFRAL^​28​. In addition, a study, published in 2019, found that circulating levels of GDF15 and IGFBP7 are significantly elevated in patients hospitalised at 12 weeks’ gestation with HG, compared with patients with normal or no NVP^​29​. At 24 weeks’ gestation, when symptoms have largely resolved, the study results show that there is no difference in GDF15 and IGFBP7 serum levels between cases and controls^​29​. These studies illustrated that placentation, appetite and cachexia genes GDF15 and IGFBP7 are linked to HG. The GDF15 gene is shown to activate the vomiting centre of the brain, causing nausea and vomiting in animal models^​29,30​. 

Definition of HG

In 2021, an international consensus on the definition of HG was developed to assist in clinical diagnosis and harmonise the HG definition for clinical study populations, which is called the ‘Windsor definition’. It describes HG as^​31​:

• Onset of symptoms before 16 weeks gestational age — without other cause; 
• Nausea and vomiting — at least one of which is severe; 
• Inability to eat and/or drink normally; 
• Strongly limits daily living activities; 
• Signs of dehydration are considered to be contributory to diagnosis.

Royal College of Obstetrics and Gynaecology green-top guideline

In early 2024, the Royal College of Obstetrics and Gynaecology (RCOG) updated its green-top guideline, entitled ‘The management of nausea and vomiting in pregnancy and hyperemesis gravidarum’^​6​. It includes the Windsor definition of HG and covers tools for the diagnosis and assessment of NVP and HG, the recommended management of these disorders, the safety and efficacy profiles of relevant medicines, the impact on quality of life and mental health of the woman and the roles of multidisciplinary team (MDT) members to manage these conditions^​6​.

Assessment and diagnosis

The initial assessment for NVP/HG includes taking the patient’s history and undertaking a clinical examination. The vital signs are checked, and body weight is measured. Urine tests and blood tests should also be carried out. RCOG’s green-top guideline provides a full guide to examination and investigations to aid diagnosis and to exclude other causes of severe nausea and vomiting in pregnancy^​6​.

The RCOG guideline also recommends using an objective and validated index of nausea and vomiting, such as the Pregnancy-Unique Quantification of Emesis (PUQE) questionnaire^​32​ and Hyper-Emesis Level Prediction (HELP) score^​33​. Combined with a HELP or PUQE score, clinical assessment can assess the severity of NVP and HG^​6​.

The PUQE questionnaire has been modified to record symptom profile over the previous 24 hours, including a wellbeing score that correlates with hydration status over the duration of the first trimester^{​34–36​}. The PUQE-24 can be used to assess the severity of NVP and treatment response for mild-to-moderate NVP, but it is not valid for severe NVP and HG^​6​.

The HELP score can be used over time to monitor progress and response to treatment^​33​. It is available as an online calculator and in app form (i.e. the HG Care App). In addition to assessing severity of symptoms, the HELP score can track treatment response in severe NVP and HG^​6​.

NVP and HG can lead to hyponatraemia, hypokalaemia, low serum urea, raised haematocrit and ketonuria with a metabolic hypochloraemic alkalosis^​6​. In severe cases, metabolic acidosis may develop^​6​. In two-thirds of patients diagnosed with HG, there may be abnormal thyroid function. These patients rarely have thyroid antibodies and are euthyroid clinically. The biochemical thyrotoxicosis resolves as the HG improves, and treatment with anti-thyroid drugs is usually not required^​35​. As a result, a raised T4 (thyroxine) and low TSH (thyroid-stimulating hormone) do not require treatment in straightforward NVP/HG cases where the cause is clear and the patient is responding to NVP/HG treatment^​6​.

Liver function tests (LFTs) show abnormal results in up to 40% of women with HG^​37​. The most common abnormality of liver enzymes is a rise in transaminases. Levels of bilirubin and amylase may be mildly elevated; however, abnormal LFTs should improve as the HG resolves^​6​. 

Ketonuria is not an indicator of dehydration and should not be used to assess the severity of NVP or HG^​38,39​. Assessment of urinary ketosis may mislead clinical judgement of hydration and nutrition status, so it should be avoided in the assessment of NVP and HG^​6​.

Severe malnutrition can be assessed with anthropometric measures such as mid-upper arm circumference and validated nutrition screening tools (e.g. the Malnutrition Universal Screening Tool, which can be adapted for pregnancy)^{​40–43​}.

Care management in different settings

Community care and at home

Women who have NVP symptoms but are not dehydrated can be cared for in the community with antiemetics, reassurance, oral hydration and dietary advice (i.e. eat little and often to prevent an empty stomach)^​6​. Women should be advised to rest and to take time off work if necessary. 

For women who are unable to maintain hydration orally but do not have other comorbidities or complications caused by NVP, ‘hospital at home’ services can administer IV rehydration treatment by a community midwife/nurse. If IV fluid containing potassium chloride is required for the patient in a ‘hospital at home’ setting, risk assessment should be carried out to decide whether it is safe to give such an IV regimen at home. A local guideline should be developed using a MDT approach to mitigate the medication risk. 

If total parenteral nutrition (TPN) is administered to the patient at home, it is important that the community midwives have received training regarding TPN administration and have the knowledge to address any complications that arise.

Although most antiemetics are unlicensed in pregnant women, the absolute risk to the foetus from antiemetics drugs used in HG patients is low^​44​. As a result, the benefits of antiemetics are considered to outweigh the risks in women with NVP. These antiemetics should be offered by the prescribers in the community as appropriate^​45​.

Ambulatory day care

If women are unable to tolerate oral antiemetics or oral fluids, ambulatory day care, which provides IV fluids, vitamins — especially thiamine^​46,47​ — and parenteral antiemetics, is appropriate to offer as stepwise management. According to the results of a randomised, controlled trial (RCT) of 98 women, published in 2014, ambulatory day care management involving IV fluids and stepwise increments in antiemetic therapy was acceptable and resulted in fewer days as an inpatient^​48​. In another study, published in 2004, improvement in NVP symptoms occurred in 89.3% of the 428 participants who received ambulatory day care subcutaneous metoclopramide therapy (SMT)^​49​. In addition to the SMT regimen, women received adjuvant therapies at home, such as hydration via the IV route, subcutaneous ondansetron, H₂-receptor blockers and IV TPN^​6​. Ambulatory day care management has been shown to be successful and safe for NVP patients^​50​.

In-patient admission

Women who have recurrent or ongoing NVP/HG, despite adequate ambulatory day care treatment, should be cared for as inpatients owing to associated complications, in particular electrolyte imbalance and nutritional deficiencies^​6​.

Inpatient care should be considered if there is at least one of the following factors^​6​:

• Continued nausea and vomiting and inability to keep down oral antiemetics;
• Continued nausea and vomiting associated with clinical dehydration or weight loss (i.e. more than 5% of body weight), despite oral antiemetics;
• Confirmed or suspected comorbidity (e.g. urinary tract infection, inability to tolerate oral antibiotics);
• Comorbidities such as epilepsy, diabetes, HIV, hypoadrenalism or psychiatric disease where symptoms and inability to tolerate oral intake and medication could present further complications.

Trophoblastic disease and multiple pregnancy are associated with an increased risk of HG. When inpatient care is required, an ultrasound scan should be scheduled to confirm gestational age and assess for multiple pregnancy or trophoblastic disease^​6​.

Pharmacological options

The RCOG green-top guideline, the Cochrane review, other systematic reviews and meta-analyses and birth-registry data support the safety and efficacy of antiemetic therapies for the management of NVP and HG, with no increased risk of teratogenesis or other adverse pregnancy outcomes^​5,51​. These drugs include:

• Antihistamines (i.e. H1 receptor antagonists), including promethazine, cyclizine, cinnarizine, pyridoxine-doxylamine (Xonvea) and dimenhydrinate; 
• Phenothiazines, including prochlorperazine, chlorpromazine and perphenazine; 
• Dopamine antagonists, including metoclopramide and domperidone.

All the antiemetics mentioned above can be used with confidence in both primary and secondary care to manage women’s symptoms in NVP and HG^​6​.

The RCOG green-top guideline recommends that prescribers to use antiemetics from different classes if the first drug is not effective or only partially effective^​6​. Many patients will require a combination of two or more drugs to manage NVP.

When selecting an antiemetic, bear in mind that some have the Medicines and Healthcare products Regulatory Agency (MHRA) and European Medicines Agency (EMA) medication safety alerts. Monitoring and patient counselling are essential from the healthcare staff while the women are taking these drugs. For antiemetic therapies recommended by RCOG^​6​, see Tables 1–3^{​6,52–57​}.

A slow-release combination tablet of the antihistamines doxylamine 10mg (H₁ receptor antagonist) and pyridoxine 10mg (vitamin B₆) called Xonvea is the only licensed therapy in the UK to treat mild-to-moderate NVP^{​6,57,58​}. Other antiemetics are unlicensed in pregnancy. This combination oral formulation has been available in Canada since 1979, in the United States since 2013 and in the UK since early 2024^​57​.

The results of a randomised, double-blind, multicentre trial of 256 women, published in 2019, found that the combination of doxylamine and pyridoxine led to a larger improvement in PUQE score from baseline to day 15 compared with placebo. There was also a significant increase in wellbeing score with active treatment^​58​. Although there is no high-quality evidence that this slow-release formulation is more effective than other, unlicensed, antiemetics in treating NVP, there is evidence from other fields, such as chemotherapy nausea and vomiting management, that supports the use of Xonvea^​58​.

Three small, randomised studies demonstrated that ondansetron is superior to doxylamine with pyridoxine in reducing the symptoms of nausea and vomiting^​59​. However, since there are large amounts of safety data for doxylamine with pyridoxine and antihistamines in general have fewer adverse effects than ondansetron, which may cause constipation, antihistamines remain first-line over ondansetron^​6​. A Cochrane systematic review, published in 2017, found that ondansetron improved symptoms of all severities in HG^​51​.

Several large epidemiological studies of ondansetron for NVP/HG have shown a small increased risk of cardiac defects or orofacial clefting^​60​. In August 2019, the EMA Pharmacovigilance Risk Assessment Committee (PRAC) recommended that all marketing authorisation holders for ondansetron-containing medicines update their product literature to state that ondansetron-containing medicines should not be used in the first trimester of pregnancy^​61​.

In response to EMA PRAC recommendations, the UK Teratology Information Service (UKTIS) said that although findings of the study appeared robust, the absolute increase in risk of orofacial cleft following first trimester maternal ondansetron use was very small, affecting approximately 14 per 10,000 births, compared with a background rate of 11 per 10,000 unexposed pregnancies^​61​. For these reasons, UKTIS and the European Network of Teratology Information Services do not support the recommendations made by EMA PRAC. They have suggested that the recommendations may result in less effective control of maternal nausea and vomiting, increased maternal morbidity and hospitalisation, and an increased risk of termination of wanted pregnancies^​61​.

Owing to the risk of extrapyramidal effects with metoclopramide, it should be used as second-line antiemetic therapy^​52​. The EMA Committee for Medicinal Products for Human Use has confirmed the risk of short-term extra-pyramidal disorders and tardive dyskinesia, particularly in young people^​62​. Despite the EMA’s recommendation, the RCOG guideline recommends that metoclopramide can be prescribed for more than five days in women who gain clinical benefits from it for HG^​6​.

Various drug classes have different mechanisms of action that can work synergistically when prescribed together^​6​. As a result, a combination of different antiemetics is recommended in women who do not respond to a single agent. Some women may require combinations of two or more medications from first and second-line options^​6​.

For women with persistent or severe HG, oral antiemetics may not be absorbed systemically. Sublingual, IV, rectal, transcutaneous or intramuscular routes may be more effective.

As Table 3 shows, corticosteroids are the third-line option of antiemetic therapies. Corticosteroids should be only used after conventional treatment with IV fluid replacement and regular antiemetics have been attempted and proven to be ineffective^​6​. They showed dramatic and rapid improvement in a case series of women with refractory HG^​63​. However, the results of some RCTs are conflicting^​64​. The RCOG guideline recommends the initial dosage to be IV hydrocortisone 100mg, twice daily^​6​. Once the clinical improvement occurs, the dose will be converted to oral prednisolone 40–50mg daily, with the dose gradually tapered (i.e. 5–10mg per week) until the lowest maintenance dose that controls the symptoms is reached^​6​. In most cases, prednisolone needs to be continued until the gestational age at which HG would have resolved and, in some extreme cases, prednisolone is continued until birth^​65​. Prednisolone is commonly used as the oral corticosteroid for HG owing to its safety profile^​61​.

Women receiving corticosteroids should be screened for gestational diabetes owing to the side-effect profile of steriods^​6,52​. The pharmacist should provide patients with clear advice regarding self-management of reducing dose regimen of prednisolone at discharge, with a steroid card given to the patient, as recommended in the British National Formulary^​52​. The pharmacist should also ensure that the patient has proton-pump-inhibitor cover for the duration of the steroid course as gastric protection. Blood pressure and blood glucose should be monitored during the course.

Although oral ginger was recommended for the management of HG^​66​ in the past, it is no longer recommended according to the RCOG guideline and the latest evidence^{​6,67,68​}. A large, cross-sectional survey, published in 2015, found that ginger and over-the-counter tablet formulation have little or no efficacy for HG, which also caused unpleasant adverse effects and worsening of symptoms in over half of the group^​68​. If a healthcare professional recommends ginger as an antiemetic for NVP, it may cause a loss of trust and potentially damage the healthcare staff–patient relationship^​6​. Using ginger as a therapy for HG could also delay the patient receiving more effective treatment^​6​.

Optimal IV regimens for ambulatory care and in-patient settings

IV fluid management and electrolyte replacement are the most important interventions in managing severe NVP and HG^​6​. IV fluids have been shown to reduce vomiting and also correct dehydration and electrolyte disorders^​6​. There is no evidence to determine which fluid regimen is most appropriate; however, as most women admitted to hospital with HG are presented with hyponatraemic, hypochloraemic and/or hypokalaemic, it is appropriate to use 0.9% NaCl with potassium chloride infusion (i.e. a pre-mixed bag)^​6​. Urea and serum electrolyte levels should be monitored daily in women with the IV fluids prescribed, in which pharmacist can play a role in this.

Clinical studies have showed that dextrose-containing IV solutions may precipitate Wernicke’s encephalopathy in thiamine deficient states^​69,70​. Therefore, they should be avoided in NVP and HG patients^​6,70​. However, IV dextrose containing fluids are appropriate for nausea and vomiting in the third trimester to prevent and treat starvation ketosis^​6,71​. To prevent Wernicke’s encephalopathy, it is advisable to give 100mg of IV thiamine weekly in HG patients with persistent or severe late-onset vomiting^​6,70​. If the patient can take medications orally, oral thiamine 100mg three times per day can be used^​6​.

Measures to minimise the risk of complications from HG

Effectiveness of oral medications

Women with NVP and HG have difficulties tolerating oral fluids, meaning that excessive vomiting can affect other medical conditions requiring oral medication, such as epilepsy, psychiatric conditions, hypoadrenalism and HIV — it is crucial to prescribe effective antiemetics for women with these comorbidities^​6​. The timing of medication dosage may need to be adjusted so that the patients can take them when symptoms are better controlled^​6​. The absorption of oral drugs may not be very effective for patients experiencing intractable vomiting. Some centres in the UK recommend folic acid 5mg daily dose in the first trimester instead of 400 micrograms daily dose for this reason.

HG may increase risks in patients with diabetes mellitus or a history of gastric band, gastric bypass or gastric sleeve surgery^​6​. Specialist advice is required for these groups of women. A previous history of gastric reduction surgery may cause malabsorption of oral medication and increase the risk of nutrient and vitamin deficiency, particularly thiamine and vitamin K^​6​.

Gastrointestinal complications

Recurrent intractable vomiting may lead to gastro-oesophageal reflux disease, oesophagitis or gastritis^​6​. H₂-receptor blockers or proton pump inhibitors (PPI) may be used in women who develop these conditions^​6​. The treatment of gastro-oesophageal reflux, together with antiemetic therapy, has been associated with a reduction of PUQE-24 scores and improved quality-of-life scores^​72​.

Deep vein thrombosis

Patients with HG are at an increased risk of developing deep vein thrombosis owing to dehydration and their lack of mobility^​73​. Women admitted with HG should be offered thromboprophylaxis with low-molecular-weight heparin (LMWH), and patients treated in the community should be assessed for venous thromboembolism (VTE) risk^​6​. Graduated compression stockings should also be used when LMWH is contra-indicated. Since women with HG are only at markedly increased risk while persistently vomiting, thromboprophylaxis therapy can be discontinued upon discharge, providing no other co-existing indications for the continuation of thromboprophylaxis^​74​.

Constipation

Women with NVP or HG often suffer with constipation owing to reduced food and fluid intake, as well as when treated with ondansetron^​51,75​. Women should be asked about their bowel habits and offered laxatives if constipated, particularly if ondansetron is used^​6​.

As oral iron can cause nausea, vomiting and constipation as side effects^​51​, women with previous or current NVP or HG should consider avoiding iron-containing preparations if these exacerbate symptoms or consider alternative route of administering iron^​6​.

Discharge planning and reducing readmissions

Women should only be discharged if^​6​:

• Appropriate antiemetic therapy has been tolerated;
• Adequate oral nutrition and hydration has been tolerated;
• Management of concurrent conditions is completed.

Approximately, a third of women hospitalised with HG will be readmitted within the same pregnancy^​76​. Therefore, at the time of discharge, it is crucial that women are advised by the pharmacist to continue with the antiemetics as prescribed, as well as:

• Possible side effects;
• Why the different types of antiemetics have been prescribed;
• Duration of the treatment course, especially for patients on steroids;
• Medications that help counteract the side effects of some of the antiemetics;
• Any available HG counselling services;
• How to access further medications if their symptoms recur.

These counselling points aim to reduce the risk of readmission. At some hospitals, patients are advised to contact the medicines information centre within the hospital for any medicines-related questions after discharge. 

Rehydration and antiemetic medications reviews can be carried out in the ambulatory day care unit^​77​. In some hospitals, there are midwives and obstetric pharmacists with independent prescribing qualifications working in the day care unit or antenatal clinic. These healthcare staff can amend dosage or choice of treatments when appropriate after review.

A cross-sectional survey of community pharmacists in the UK assessed the content and frequency of advice community pharmacists provided to women with NVP, their confidence in providing advice, and their knowledge of the safety of medications used to manage the condition^​78​. This study, published in 2024, showed that although community pharmacists frequently provide advice on NVP and perceive this as part of their role, their knowledge of the safety of the medication used in the management of the condition is suboptimal. In addition, greater awareness is needed on evidence-based treatments that could be recommended to women for mild symptoms^​78​. Although NVP is common, only a small percentage of community pharmacists reported having prior training on the topic, while the majority reported a need for further education in the form of a continuing professional development (CPD) course^​78​.

Pregnancy Sickness Support is a charitable organisation that offers HG training courses for GPs, community pharmacists and primary care midwives^​68​. The charity produces posters and a free patient information leaflet is available from their website. It also offers a counselling service for patients with HG.

Other treatment strategies

If conventional treatment does not help control the symptoms of NVP and HG, there are other treatment strategies that can be used.

TPN

TPN should only be considered when all other treatments have failed, as it is expensive and can be associated with serious complications such as thrombosis, metabolic disturbances and infection^​79,80​. This decision should be made with the MDT, including the pharmacist, doctors and a dietitian. TPN has also been associated with a reduced risk of perinatal morbidity^​81​. Daily weight should be monitored while on TPN.

Enteral tube feeding

Enteral tube feeding options can also be considered using^​6​:

• Nasogastric or nasojejunal tubes tubes;
• Percutaneous endoscopic gastrostomy;
• Percutaneous endoscopic gastrojejunostomy.

These options should only be considered after consultation with a gastroenterologist and the MDT^​5​. Pharmacists can look at whether the prescribed oral antiemetics drugs are suitable for administration via nasogastric or nasojejunal tubes, percutaneous endoscopic gastrostomy or percutaneous endoscopic gastrojejunostomy.

Acupressure in NVP

Acupressure is a complementary medicine technique closely related to acupuncture, consisting of pressure applied (e.g. by finger, hand, elbow or stimulated by electric devices) to certain pressure points in the body^​82​. A meta-analysis, published in 2023, found there is evidence that acupressure can reduce NVP^​83​.

Another study, published in 1994, evaluated the effectiveness of acupressure in reducing nausea and vomiting of pregnancy^​84​. The results indicated that acupressure at the PC-6 site is effective in reducing symptoms of nausea but not the frequency of vomiting in pregnant women^​84​.

Termination of pregnancy

HG is associated with a higher risk of termination of pregnancy (TOP)^​85​. Approximately 10% of women with HG decide to undergo TOP owing to the severity of symptoms^​68,85​. Antiemetics, corticosteroids, enteral tube and parenteral feeding, and correction of electrolyte or metabolic disturbances should all be considered or tried first^​86,87​. Psychiatric advice should be considered if there are concerns regarding mental health, and the decision for TOP needs to be multidisciplinary^​6​. The reasons for TOP, including the therapeutic failures, should be documented clearly in the medical notes. Women should be offered counselling before and after a decision is made for TOP^​6​. 

Quality of life

NVP has been reported to reduce quality of life, impairing a woman’s ability to function on a day-to-day basis, and negatively affects relationships with partners and family^​88,89​. A cross-sectional UK study, published in 2021, examined the relationship between HG and TOP and suicidal ideation, with reference to disease severity, functional status and perception of care^​90​. The results showed that just over half of the participants considered termination of pregnancy owing to HG^​90​. One-quarter of participants reported occasional suicidal ideation, while 6.6% reported regular suicidal ideation owing to severe sickness^​90​. 

Poor mental health during the HG diagnosis may extend to the postnatal stage and increase the risk of PTSD after labour^​6​. Pharmacists who have the opportunity to be involved with the care of women with HG in clinic or on the wards can play a role in protecting mental health by assessing the severity of a woman’s symptoms in relation to her quality of life and social situation^​6​. 

Using an MDT approach

A holistic approach for assessment and management of patients should be adopted for severe NVP and HG. Input from a MDT is essential, which includes obstetricians, midwives, nurses, dieticians, pharmacists, endocrinologists, nutritionists, community team gastroenterologists, clinical psychologists and the mental health team aiming to improve the symptoms of NVP/HG and the quality of life in this group of patients. 

There is potential for pharmacy technicians to expand their roles in this area of clinical pharmacy. Some pharmacy technicians may want to focus on HG for their professional development in the community or the hospital setting. They can use their skills and knowledge to help with patient counselling on antiemetic medicines, as well as the explanation of side effects and the relevant MHRA safety alerts. 

Other examples of MDT involvement are:

• An involvement of the mental health team in women with NVP/HG may improve the ability to cope with the impact of a complicated pregnancy^​91​;
• Emotional support and psychological or specialist psychiatric care may be necessary to treat mental health issues owing to HG^​88​;
• Dieticians and gastroenterologist can be consulted regarding the role of nutritional support;
• Pharmacists can help with patient counselling on the side effects profile and clinical benefits of drug therapies and advise on the further supply of medicines after discharge.

Recurrence in subsequent pregnancies

One systemic review study carried out in 2019, found five heterogeneous studies which reported HG recurrence rates were from 15 to 81%^​92​. The incidence of HG recurrence in subsequent pregnancies is 89%^{​6,89–94​}. Women with a history of NVP/HG who take pre-emptive antiemetics before pregnancy or before the onset of symptoms have a lower recurrence rate than those who do not^​95,96​. 

In view of these findings, women who have experienced severe NVP in a previous pregnancy may benefit from initiating dietary and lifestyle changes, such as arranging childcare to facilitate rest, following a ‘little and often’ diet, and commencing antiemetics before or immediately at the start of symptoms in a subsequent pregnancy^​6,95​.