Nausea and vomiting in pregnancy

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

without volume depletion

1st line – conservative management

Back

1st line –

conservative management

Dietary modifications may include advice to eat smaller, more frequent meals and to avoid smells and food textures that cause nausea.[2]

Foods should be bland-tasting, high in carbohydrate, and low in fat. Salty foods may be tolerated early in the morning. Sour and tart liquids (e.g., lemonade) are often better tolerated than water. Eliminating supplemental iron, and substituting folic acid for iron-containing antenatal vitamins, may improve symptoms of nausea.[2]

If dietary modifications fail to improve symptoms, various alternative treatments (e.g., acupressure, acupuncture, ginger) have been evaluated in the treatment of NVP, and may be tried. Since there have been no head-to-head comparisons of the majority of these modalities, it is difficult to recommend a first-line treatment. Patients should be apprised of the various options and encouraged to try the one that they would prefer.

Acupressure may improve symptoms.[2][15] Pressure is applied to the P6 point (Neiguan point, located 3 finger-widths above the wrist on the volar surface). This may be applied using commercially available wrist bands.

Ginger supplementation has been shown to be useful in reducing symptoms.[2][15][16] It may be used alone or with acupressure and is considered safe to use in all trimesters of pregnancy. It can be taken raw, as a tea, or in tablet/capsule form.[17][18]

Primary options

ginger: 250 mg orally four times daily

without volume depletion but failed conservative management

1st line – pyridoxine and/or doxylamine

Back

1st line –

pyridoxine and/or doxylamine

If non-pharmacological methods fail, first-line pharmacological therapies include pyridoxine (vitamin B6) and doxylamine (an antihistamine).[2] One randomised controlled trial found that the combination was effective compared with placebo, but a re-analysis of the data queried the clinical significance of the findings.[19][20] The UK National Institute for Health and Care Excellence recommend doxylamine/pyridoxine in women with symptoms that have not responded to conservative management. However, there is no evidence to show how it compares with other first-line treatments.[21]

These drugs may be used alone or in combination, and are available as a proprietary combination formulation in some countries.

Both drugs are considered safe during all trimesters of pregnancy.[2]

Primary options

pyridoxine: 10-25 mg orally three times daily

and/or

doxylamine: 12.5 mg orally every 6-8 hours when required

doxylamine/pyridoxine: 20 mg/20 mg (2 tablets) orally (delayed-release) once daily at bedtime on day 1, increase gradually according to response, maximum 40 mg/40 mg (4 tablets)/day

2nd line – oral antihistamines or anti-emetics

Back

2nd line –

oral antihistamines or anti-emetics

Second-line pharmacological therapies include alternative oral antihistamines (e.g., meclozine, dimenhydrinate, diphenhydramine), phenothiazine anti-emetics (e.g., chlorpromazine, prochlorperazine), or dopamine antagonist anti-emetics (e.g., metoclopramide, domperidone).[2][22][23]

Metoclopramide should be used for up to 5 days only in order to minimise the risk of neurological and other adverse effects.[39]

Following a European review, the Medicines and Healthcare products Regulatory Agency and the European Medicines Agency have issued new recommendations concerning the use of domperidone. The review found the drug was associated with a small increased risk of potentially life-threatening effects on the heart. As a consequence, it should be used at the lowest effective dose for the shortest possible duration and the maximum treatment duration should not usually exceed 1 week. The new maximum dose recommended in adults is 30 mg/day. Domperidone is contraindicated in patients with severe hepatic impairment or underlying cardiac disease. It should not be administered with other drugs that prolong the QT interval or inhibit CYP3A4.[40]

Primary options

meclozine: 25 mg orally every 4-6 hours when required, maximum 100 mg/day

dimenhydrinate: 50-100 mg orally every 4-6 hours when required, maximum 400 mg/day

diphenhydramine: 25-50 mg orally every 4-6 hours when required, maximum 300 mg/day

metoclopramide: 5-10 mg orally every 8 hours when required for a maximum of 5 days, maximum 30 mg/day

domperidone: 10 mg orally three times daily for a maximum of 7 days, maximum 30 mg/day

Secondary options

chlorpromazine: 10-25 mg orally every 4-6 hours when required

prochlorperazine: 5-10 mg orally (immediate-release) every 6-8 hours when required

promethazine: 12.5 to 25 mg orally every 4-6 hours when required

Tertiary options

trimethobenzamide: 300 mg orally every 6-8 hours when required

with volume depletion

1st line – intravenous hydration

Back

1st line –

intravenous hydration

Patients with severe volume depletion should be rehydrated with intravenous Ringer's lactate. If Ringer's lactate is not available, saline solutions can be used, with additional potassium and sodium bicarbonate as necessary.

Glucose solutions may be used. If solutions containing glucose are considered, some physicians suggest also giving thiamine (vitamin B1) prior to administration in order to prevent Wernicke's encephalopathy.[1][2]

Intravenous fluids should be given to replace the calculated deficit, ongoing losses, and the daily fluid maintenance requirement. Volume depletion assessment should be repeated periodically, and rate of fluid therapy modified based on signs of volume depletion.

Consider – parenteral or rectal anti-emetics

Back

Consider –

parenteral or rectal anti-emetics

Additional treatment recommended for SOME patients in selected patient group

In patients with intractable vomiting, parenteral (or rectal) anti-emetic therapy (i.e., phenothiazines, dopamine antagonists, or 5-HT3 antagonists) may be necessary. Evidence suggests that ondansetron may be more effective at controlling severe vomiting than metoclopramide.[26][27]

However, in 2019 studies showed an increased risk of cleft palate following the use of ondansetron during the first trimester of pregnancy.[28] The European Medicines Agency's pharmacovigilance risk assessment committee has recommended limiting the use of ondansetron during the first trimester of pregnancy.[29] The UK Teratology Information Service and the European Network of Teratology Information Services suggest ondansetron should still be considered an option for patients with severe vomiting in pregnancy in whom first-line treatments have failed.[30] The UK Medicines and Healthcare products Regulatory Agency also issued a drug safety update for ondansetron that provides similar advice.[31]

Ondansetron should therefore be reserved as a second-line agent for the treatment of NVP.[32] Patients must be adequately counselled about the benefits of ondansetron, as well as the small increase in the risk of cleft palate that may exist.

Metoclopramide should be used for up to 5 days only in order to minimise the risk of neurological and other adverse effects.[39]

Primary options

metoclopramide: 5-10 mg intravenously/intramuscularly every 8 hours when required for a maximum of 5 days, maximum 30 mg/day

Secondary options

ondansetron: 4-8 mg intravenously every 12 hours when required

chlorpromazine: 12.5 to 25 mg intramuscularly every 4-6 hours when required

prochlorperazine: 5-10 mg intramuscularly/intravenously every 6-8 hours when required, maximum 40 mg/day

prochlorperazine rectal: 25 mg twice daily when required

promethazine: 12.5 to 25 mg intramuscularly/intravenously every 4-6 hours when required

droperidol: consult specialist for guidance on dose

Consider – proton-pump inhibitor alone or in combination with anti-emetic

Back

Consider –

proton-pump inhibitor alone or in combination with anti-emetic

Additional treatment recommended for SOME patients in selected patient group

Proton-pump inhibitors (PPIs) may be used as an alternative treatment option to parenteral or rectal anti-emetics, or in combination with them.[33] Data have demonstrated that PPIs are safe in pregnancy and are not associated with a significant increase in birth defects.[34] However, analysis of data derived from observational studies suggests that PPI use during pregnancy may be associated with a modest increased risk of asthma during childhood.[35] Of the PPIs, omeprazole has been the most studied and has well-documented safety data.

Primary options

omeprazole: 20-40 mg intravenously once daily

hyperemesis gravidarum: failed other therapies

Consider – corticosteroids

Back

Consider –

corticosteroids

Additional treatment recommended for SOME patients in selected patient group

Corticosteroids can be considered after the first trimester (their use has been associated with cleft palate in fetuses exposed in the first trimester).[2][36]

A randomised, double-blind, controlled study has demonstrated improvement in symptoms.[37]

Primary options

methylprednisolone: 16 mg orally/intravenously every 8 hours for 3 days, then taper gradually over 2 weeks

prednisolone: 40-75 mg orally once daily

Consider – nutritional supplementation

Back

Consider –

nutritional supplementation

Additional treatment recommended for SOME patients in selected patient group

In extreme cases, patients may require enteral feeding or total parenteral nutrition to provide calories and replace electrolytes and nutrients. Consultation with specialists from maternal-fetal medicine and gastroenterology, and the inpatient parenteral nutrition service, is required.

Enteral feeding has been shown to be effective in one small study utilising a nasogastric tube with infusion rates up to 100 mL/hour.[38]

Helicobacter pylori-positive

Consider – Helicobacter pylori eradication therapy

Back

Consider –

Helicobacter pylori eradication therapy

Additional treatment recommended for SOME patients in selected patient group

In severe cases, patients who test positive for Helicobacter pylori may be treated with standard eradication regimens.[7]

There are many different regimens available; consult specialist for guidance on choosing the most appropriate regimen for a pregnant woman.

Use of this content is subject to our disclaimer

Nausea and vomiting in pregnancy

Treatment algorithm

without volume depletion

conservative management

Primary options

without volume depletion but failed conservative management

pyridoxine and/or doxylamine

Primary options

oral antihistamines or anti-emetics

Primary options

Secondary options

Tertiary options

with volume depletion

intravenous hydration

parenteral or rectal anti-emetics

Primary options

Secondary options

proton-pump inhibitor alone or in combination with anti-emetic

Primary options

corticosteroids

Primary options

nutritional supplementation

Helicobacter pylori eradication therapy