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Nausea & Vomiting in Early Pregnancy

NHS Tayside RefGuide
NHS Tayside

Who to refer

  • There is a PUQE greater than 6 or
  • Outpatient management has been inadequate or
  • Oral antiemetics cannot be tolerated or
  • There has been weight loss of 5% or
  • Confirmed or suspected co morbidity such as infection that cannot be managed in the community or
  • The clinical picture suggests further assessment and intervention is required or
  • Concerns regarding mental health or
  • Co-morbidity and inability to take medications (for example in women with epilepsy)

How to refer

  • The Early Pregnancy Assessment Clinic (EPAC) does not manage patients with NVP or HG.
  • All cases requiring secondary care input should be discussed with the on-call gynaecology registrar up to 13+6 weeks and the on-call obstetric registrar 14 weeks.
  • Those seen for ambulatory or inpatient management in current pregnancy can self-refer back to the gynaecology assessment unit (up to 13+6 weeks) and maternity triage (from 14 weeks) as needed throughout pregnancy if symptoms worsen or recur.

Summary 

  • Nausea and vomiting of pregnancy (NVP) affect up to 90% of pregnant women with up to 3.6% experiencing hyperemesis gravidarum (HG).
  • NVP is defined as the symptoms of nausea and vomiting during pregnancy when onset is prior to 16 weeks gestation where there are no other causes.
  • HG is defined as the above combined with the inability to eat and drink normally, strongly limiting daily living activities.
  • The severity of the condition can be assessed using the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) Score and signs of dehydration may also be contributory to the diagnosis

Primary Care Management 

  • Women can be managed by their GP when they are not dehydrated, have no complications or co-morbidities (such as diabetes or epilepsy) and can tolerate oral antiemetics/ Have a PUQE score less than or equal to 6.
  • IM prochlorperazine/ IM cyclizine can be given as part of community management. When this is not available consider referral for day case management.
  • The presence of urinary ketones does not correlate with symptom severity and should not be a regarded as a prerequisite to starting treatment or referring for secondary care management.
  • The potential severe psychological impact should always be considered and discussion with secondary care initiated in those voicing concerns regarding deterioration in mental health, suicidal ideation or thoughts of ending a wanted pregnancy.
  • Anti-emetics should be provided on an acute prescription to ensure regular medication review.
  • Anti-emetics may be gradually reduced as symptoms improve and as tolerated with the expectation that the majority will be able to stop medications by 20 weeks.
  • NVP/HG tends to recur in subsequent pregnancies therefore patients may express a preference for medication choice based on previous experience and this should be supported.
  • Pre-emptive antiemetics may help
  • Some may require multiple anti-emetics to achieve symptom control.
  • There is a potential association between ondansetron use and an increased risk of cleft lip/palate; this should only be commenced in secondary care or following discussion with obstetrics or gynaecology on call registrar. There is no risk if commenced after 12 weeks as the embryonic palate has closed by this gestation.
  • Patient information leaflets on safety of use can be accessed from 'bumps' - best use of medicine in pregnancy (Bumps - Best use of medicines in pregnancy) to reassure and inform. 
  • All women should be advised of support available through Pregnancy Sickness Support, see Get support (pregnancysicknesssupport.org.uk)


Recommended anti-emetics

  • Where a single first line anti-emetic in ineffective, try a combination of two first line anti-emetics from different classes before adding a second line anti-emetic. Please note drug interactions listed below.
  • Promethazine, cyclizine and prochlorperazine use in the latter part of the third trimester may cause adverse effects in neonates such as irritability, paradoxical excitability, and tremor.

1st line

  • Prochlorperazine oral 10mg 6-8 hourly with max 3 doses in 24 hours; 12.5mg 8 hourly IM
    • Please note: Drug-induced extrapyramidal symptoms and oculogyric crises can occur with phenothiazines (prochlorperazine and chlorpromazine).

 

  • Xonvea (Doxylamine & Pyridoxine) 20/20mg at night, increased to additional 10/10mg in the morning and 10/10mg at lunchtime if required (the only licensed treatment of NVP in the UK).
    • Both Doxylamine (Xonvea) and Chlorpromazine, and Doxylamine (Xonvea) and prochlorperazine have effects on the CNS and can cause sedation, which might affect the ability to perform skilled tasks (see 'Drugs and Driving' in Guidance on Prescribing). In some cases, use of two or more drugs that have effects on the CNS might also increase the risk of CNS depressant effects (which could range from sedation to unconsciousness, coma, respiratory depression, and/or cardiovascular depression).

 

  • Cyclizine 50mg 8 hourly oral/IM/IV

 

  • Promethazine5-25mg 4-8 hourly oral/IM/IV/PR.
    • Avoid using in combination with chlorpromazine. Both chlorpromazine and promethazine have some risk of prolonging the QT interval, which might lead to the potentially fatal torsade de pointes arrhythmia. Dangerous QT prolongation might occur if they are used together.
    • Please advise women regarding the significant sedating effects of promethazine as well as all other first line antiemetics. Women should not drive, or operate machinery if affected.

 

  • Chlorpromazine 10-25mg 4-6 hourly oral/IM/IV.
    • Avoid using in combination with promethazine.
    • Please note: Drug-induced extrapyramidal symptoms and oculogyric crises can occur with phenothiazines (prochlorperazine and chlorpromazine).

2nd line

  • Metoclopramide 5-10mg 8 hourly oral/IM/IV. Trial first for a maximum of 5 days but RCOG guidance states “recommend that it can be prescribed for more than five days in those women who gain symptomatic relief from it. [Evidence level 2++]”. See BNF for dosing for women under 60kg or under 18 years of age.

 

 

  • Ondansetron 4-8mg 6-8 hourly PO/IM/IV. Consider laxatives. Background risk of cleft is 11/10000. Risk with ondansetron use 14/10000. There is no risk after 12 weeks gestation as the embryonic palate has closed.
    • Potential of QT prolongation in combination with domperidone, promethazine or chlorpromazine.

Editorial Information

Last reviewed: 09/02/2026

Next review date: 09/02/2028

Reviewer name(s): lawrize.stofberg1@nhs.scot, tay.referralguidance@nhs.scot.