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Written by The HG Collective · Reviewed by HG Clinicians Expert Panel · Last reviewed: July 2026

Treating pregnancy sickness and HG

Most people with mild, usual pregnancy sickness can manage their symptoms themselves and will not need medication. For others, symptoms do not settle, begin to interfere with daily life or make eating and drinking difficult. In that situation, anti-sickness medication may help. Hyperemesis gravidarum (HG) is at the severe end of pregnancy sickness and usually needs active medical treatment.

Care should be based on how severe your symptoms are, whether you can eat and drink, how symptoms affect daily life and how you respond to treatment. You do not need to wait until you are dehydrated, losing weight or meet the definition of HG before asking a healthcare professional for help.

If you do need treatment, there is no single option that works for everyone. The plan may need to be adjusted, particularly with HG. You may need more than one anti-sickness medicine, a different way of taking it, intravenous fluids or hospital-based care. Needing further treatment does not mean you have failed—it means the plan needs to change.

Food, fluids and practical measures

For mild pregnancy sickness, practical measures may be all that is needed. If symptoms persist, interfere with normal activities or make it difficult to eat or drink, these measures should support appropriate treatment—not replace it or delay medical care.

If you can eat or drink, it may help to:

  • have small amounts regularly rather than trying to manage a full meal or large drink;
  • choose whatever food and fluid you can tolerate—this may change from one day to the next;
  • try cold foods or drinks if cooking smells make symptoms worse;
  • keep tolerated snacks and drinks within easy reach;
  • separate food and fluids if taking them together is difficult;
  • rest when you can and reduce exposure to personal triggers, such as strong smells, heat, movement, light or noise; and
  • accept practical help with cooking, childcare, work and household tasks.

Some people find plain or carbohydrate-based foods easier, but there is no single “HG diet”. The immediate priority is getting in what you can. You should not be made to feel guilty if your diet is limited while you are unwell.

Some people try P6 acupressure wristbands. A small trial reported improvement when acupressure was used alongside standard inpatient treatment, but the evidence is limited. Acupressure should only be used as an addition to appropriate treatment.

Ginger is sometimes suggested for ordinary pregnancy sickness, but evidence from ordinary nausea and vomiting in pregnancy should not be assumed to apply to HG. RCOG advises healthcare professionals not to suggest ginger for HG. Many people with HG have already tried it, and a survey of people previously hospitalised with HG found it was usually ineffective and could cause unpleasant effects or worsen symptoms.

Anti-sickness medication—a step-by-step approach

Not everyone with pregnancy sickness needs medication. If mild symptoms are manageable and you can eat, drink and continue your usual activities, self-care may be enough. If symptoms do not settle, affect daily life or make eating and drinking difficult, anti-sickness medication can be used in pregnancy, including during the first trimester. You do not need to wait until you are dehydrated or losing weight before asking for help.

RCOG recommends a stepwise approach:

  • First-line options include doxylamine/pyridoxine (Xonvea®), antihistamines such as cyclizine or promethazine, and phenothiazines such as prochlorperazine or chlorpromazine.
  • Second-line options include ondansetron, metoclopramide and domperidone. These may be used when first-line medicines have not worked well enough or have caused unacceptable side effects for the pregnant person.
  • Third-line treatment means corticosteroids. These are reserved for severe cases that have not responded to intravenous fluids and regular anti-sickness medicines.

“First-line” and “second-line” do not mean that one medicine will work better for everyone. The order is based largely on the available pregnancy-safety evidence and recognised side effects for the pregnant person. If one medicine is not enough, RCOG recommends combining medicines from different drug classes rather than simply continuing with ineffective treatment.

If you cannot keep tablets down, ask about another route. Depending on the medicine and local service, treatment may be available as a buccal or rectal preparation, or by injection, infusion or another non-oral route. The correct route matters: a medicine cannot help if it is repeatedly vomited back up.

Do not change the dose, combine medicines or stop corticosteroids without medical advice. If you develop an unusual reaction—such as muscle spasms, abnormal movements, severe restlessness or marked stiffness—seek medical advice promptly.

Understanding medication safety

It is completely understandable to worry about taking medication during pregnancy. Two different questions are often grouped together, so it can help to separate them:

  • Side effects are unwanted effects the pregnant person may experience while taking a medicine, such as drowsiness, constipation, restlessness or movement-related reactions. The possible side effects differ between medicines.
  • Pregnancy safety means the evidence about whether a medicine may affect the pregnancy or developing baby. This is a separate question and must be considered medicine by medicine.

The decision is not between taking a medicine and having a risk-free pregnancy. When symptoms are severe, poorly controlled HG also carries risks, including dehydration, malnutrition, electrolyte disturbance, blood clots and serious effects on physical and mental health.

Many of the anti-sickness medicines recommended by RCOG have extensive and reassuring pregnancy safety data. Medicines can still cause side effects for the pregnant person even when the evidence about the baby is reassuring. The balance of benefits and risks is not identical for every person or every medicine. Your clinician or pharmacist should explain why a medicine is being offered, the common side effects you might experience, the specific evidence about use in pregnancy and what to do if it does not work.

If you are worried about a prescription, ask for an individual risk–benefit discussion rather than stopping it without advice. You may also find the independent patient information from Best Use of Medicines in Pregnancy (BUMPS) helpful.

Fluids, vitamins and hospital-based treatment

If you cannot drink enough, keep medication down or manage safely at home, you may need ambulatory day care or admission to hospital. Treatment can include:

  • fluids through a drip;
  • anti-sickness medication by a route you can absorb;
  • blood tests and correction of electrolyte disturbances;
  • vitamin B1 (thiamine);
  • assessment and treatment of complications; and
  • blood-thinning injections when indicated to reduce the risk of a blood clot.

Why thiamine matters

Thiamine stores can become depleted when food intake has been severely reduced or vomiting has continued. Severe deficiency can cause Wernicke's encephalopathy, a rare but serious and preventable neurological condition.

RCOG says thiamine should be given to everyone admitted with vomiting or severely reduced dietary intake, especially before dextrose (glucose) or parenteral nutrition. Dextrose is not recommended as routine replacement fluid for NVP or HG because it can trigger or worsen Wernicke's encephalopathy in someone who is thiamine deficient.

This is a clinical safety responsibility for the treating team. You should not have to manage the order of intravenous treatment yourself.

Fluids and blood-clot prevention

For intravenous rehydration, RCOG recommends sodium chloride 0.9% with potassium added as needed, guided by daily electrolyte monitoring. The exact fluid, amount and rate must be prescribed for the individual.

People admitted with HG should be offered an assessment and, where appropriate, low-molecular-weight heparin injections to prevent venous thromboembolism. People treated in the community should also have their individual blood-clot risk considered.

If symptoms continue despite treatment

If treatment is not controlling your symptoms, the answer should be a review and escalation of care—not simply being told to persevere. Your team may need to:

  • check that medication is being absorbed and taken at effective intervals;
  • change the route or combine medicines from different classes;
  • treat reflux, gastritis or constipation that is making symptoms worse;
  • arrange dietetic advice or oral nutritional supplements;
  • assess your physical health, mental health and social circumstances;
  • involve obstetric medicine, gastroenterology, pharmacy, dietetics or other specialists; or
  • consider enteral tube feeding or parenteral nutrition in severe, refractory cases after other medical treatments have failed.

Tube feeding and parenteral nutrition are specialist treatments with important risks. They are not routine early treatment, but they should remain available as part of multidisciplinary care when symptoms and nutritional intake cannot be managed by other measures.

If your symptoms worsen again after initial improvement, contact your healthcare team. HG treatment often needs ongoing prescriptions, follow-up and adjustment rather than a single episode of care.

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