The management of nausea and vomiting during pregnancy

Recommendation

Strength

Diagnosis of nausea and vomiting during pregnancy

NVP is diagnosed when onset is prior to 16 weeks of gestation and other causes of nausea and vomiting have been excluded.

Strong

HG is diagnosed when symptoms start in early pregnancy, nausea and/or vomiting are severe enough to cause an inability to eat and drink normally and strongly limits daily activities of living (see the differential diagnosis of NVP in appendix1).

Strong

An objective and validated index of nausea and vomiting such as the PUQE tool (see appendix 2) can be used to classify the severity of NVP and HG.

Conditional

Clinicians should be aware of the features in history, examination and investigation that allow appropriate assessment of NVP and HG and to monitor severity.

Strong

Ketonuria is not an indicator of dehydration in pregnancy and should not be used to assess severity.

Strong

Non-Pharmacological therapies of NVP and HG

Avoid an empty stomach at all times, with small and frequent meals every 1–2h.

Strong

Prevent a full stomach (ie. not mixing solid with liquid, avoiding large meals).

Strong

Eat dry food, high-protein snacks, and crackers in the morning before arising.

Strong

Avoid strong tasting and spicy food, eliminate supplemental iron.

Strong

Ginger, has shown a beneficial effect in reducing nausea symptoms, but not in reducing vomiting.

Strong

We recommend against acupuncture, acupressure and hypnosis.

Strong

Pharmacological therapies

Combinations of different drugs should be used in women who do not respond to a single antiemetic.

GPS

For women with persistent or severe HG, non-oral routes may be necessary and more effective than an oral regimen

Conditional

Stepwise approach for mild and moderate NVP without hypovolemia:

-     Doxylamine/pyridoxine (vitamin B6) is recommended as the first-line therapy for mild-moderate NVP: Doxylamine/pyridoxine 20/20mg PO at night, increase additional 10/10 mg in morning and 10/10mg at lunchtime if required.

If no adequate response, ADD antihistaminic:

-     Cyclizine 50 mg PO, IM or IV 8 hourly

-     Promethazine 12.5–25 mg 4–8 hourly PO, IM or IV.

If no adequate response, ADD dopamine antagonists:

-     Prochlorperazine 5–10 mg 6–8 hourly PO (or 3 mg buccal); 12.5 mg 8 hourly IM/IV; 25 mg PR daily.

-     Metoclopramide 5–10 mg 8 hourly PO, IV/IM/SC.

-     Domperidone 10 mg 8 hourly PO; 30 mg 12 hourly PR.

If no adequate response, ADD:

-     Ondansetron 4 mg 8 hourly or 8 mg 12 hourly PO; 8 mg over 15 minutes 12 hourly IV; 16 mg daily PR (Women taking ondansetron may require laxatives if constipation develops).

If no adequate response, ADD:

-     Hydrocortisone 100 mg twice daily IV and once 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 (Corticosteroids should be reserved for cases where standard therapies have failed; when initiated they should be prescribed in addition to previously started effective antiemetics.

-     Women taking corticosteroids should have their blood pressure monitored and a screen for diabetes mellitus).

Strong

Acid-reducing agents can be used as adjunctive therapy in patients with heartburn/acid reflux and NVP.

Conditional

In women with severe NVP or HG, input could be sought from other allied professionals.

Conditional

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.

Conditional

Histamine type-2 receptor blockers or proton pump inhibitors may be used for women developing gastro-oesophageal reflux disease, oesophagitis or gastritis.

Conditional

Management of NVP-HG with hypovolemia

Hospital admission for close monitoring and ongoing treatment is appropriate for those with persistent inability to tolerate oral intake resulting in hypovolemia requiring intravenous replacement fluid, and failure of oral and/or intravenous antiemetic therapy.

Strong

The goal of inpatient management is to restore oral intake to enable adequate hydration and nutrition and use of oral antiemetic therapy after discharge.

Strong

The decision to discharge needs to be individualized based on the patient's ability to access outpatient resources.

Strong

A baseline electrocardiogram is indicated in patients with electrolyte abnormalities requiring replacement.

Strong

Fluid replacement:

-   Aggressively rehydrate with up to 2 liters of IV crystalloid over two hours (preferably with lactated Ringer's due to decreased incidence of acute kidney injury compared with normal or isotonic saline).

-   After initial resuscitation, titrate IV fluids to maintain urine output at least 100 mL/hour or continue at a rate of 125 to 150 mL/hour, with close monitoring of oral intake and urine output.

-   Then switch to dextrose-saline (dextrose 5% in 0.45% saline) at a rate of 150 mL/hour. For patients with normal potassium levels, add 10 mEq potassium chloride for each 500 ml.

Strong

Urea and serum electrolyte levels should be checked daily in women requiring intravenous fluids.

In patients with electrolyte imbalance, consult intensive care specialist to correct the imbalance.

GPS

Thiamine:

-   To reduce the risk of Wernicke encephalopathy, 100 to 200 mg thiamine (vitamin B1) should be added to the initial fluid resuscitation and then daily thereafter while the patient is taking nothing-by-mouth or for two to three days in patients with oral intake.

-   If Wernicke encephalopathy is suspected, treat with 200 to 500 mg IV every eight hours for 2 to 7 days, followed by 250 mg once daily for an additional 3 to 5 days, followed by maintenance therapy 100 mg daily until no longer at risk for deficiency. Thiamine should be administered before administering glucose.

Strong

Other vitamins:

-   A multivitamin may be given intravenously each day (folic acid and pyridoxine).

-   Vitamin K addition is not necessary unless to treat a coagulopathy (add 150 mcg vitamin K).

Conditional

Antiemetics:

-   Begin with ondansetron 4 mg intravenously (IV push) once every eight hours upon hospitalization for intravenous fluid therapy and may increase to 8 mg IV every eight hours. After the patient has stabilized, ondansetron is discontinued. OR

-   Intravenous dimenhydrinate 50 mg every four to six hours, metoclopramide 5 to 10 mg every eight hours, or promethazine 12.5 to 25 mg every four to six hours is an alternative to ondansetron.

-   Parenteral medications can be discontinued and oral medications started after 24 to 48 hours of gastrointestinal rest and when the patient is tolerating oral intake.

Strong

Thromboprophylaxis:

-   Women admitted with HG should be offered thromboprophylaxis with low-molecular-weight heparin and those being managed as outpatients should be assessed for VTE risk.

-   Graduated compression stockings should be used when low-molecular-weight heparin is contra-indicated.

-   Thromboprophylaxis can be discontinued upon discharge providing no other indications exist for continuation of thromboprophylaxis.

Strong

Management of patients with refractory NVP and HG

Consider testing for H. pylori infection in patients unresponsive to standard therapy, who have symptoms beyond the first trimester, who require multiple hospitalizations, or who have symptoms of gastroesophageal reflux disease.

Conditional

Enteral or parenteral nutrition

When all other medical therapies have failed to sufficiently manage symptoms, enteral tube feeding or parenteral nutrition should be considered with a referral to a specialized physician in clinical enteral and parenteral nutrition in parallel to ongoing medical therapies.

Strong

Hospitalization

Inpatient care should be considered if there is at least one of the following:

-     Continued nausea and vomiting and inability to keep down oral antiemetics.

-     Continued nausea and vomiting associated with clinical dehydration or weight loss (greater than 5% of body weight), despite oral antiemetics.

-     Confirmed or suspected comorbidity (such as urinary tract infection and 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.

GPS

Antenatal care after hospital discharge

Women should only be discharged once:

-     Appropriate antiemetic therapy has been tolerated.

-     Adequate oral nutrition and hydration have been tolerated.

-     Management of concurrent conditions is completed.

GPS

At the time of discharge, it is essential that women are advised to continue with their antiemetics for at least one week and that they know how to access further care.

Strong

Women with severe NVP or HG who have continued symptoms into the late second or the third trimester should be offered serial scans to monitor fetal growth.

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Long-term effects of NVP and HG on women

There is no evidence of significant impact on long-term all-cause mortality.

Strong

Women who experience HG in pregnancy are at increased risk of PND, anxiety, and PTSD

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Women with previous HG should be advised that there is a risk of recurrence in future pregnancies.

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Future pregnancies

Early use of lifestyle/ dietary modifications and antiemetics that were useful in the index pregnancy is advisable to reduce the risk of NVP and HG in the current pregnancy

Strong