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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Pain relief in labour

Obstetrics and gynaecology · UK scope · Sources checked 7 Sept 2026 · Clinical review pending

RapidFull
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Respiratory depression or an unexpectedly high block

Marked drowsiness, slow or absent breathing, falling oxygen saturation, rapidly ascending numbness, arm weakness or cardiovascular collapse after analgesia requires immediate assessment. Do not attribute reduced responsiveness to exhaustion alone.

Action: Stop the implicated opioid or neuraxial administration, call the anaesthetist and emergency team, and assess airway, breathing and circulation. Provide oxygen and ventilatory support as required, position to reduce aortocaval compression and begin the appropriate anaesthetic emergency pathway while monitoring the fetus.

Synopsis

Help patients choose effective labour analgesia, explain important trade-offs, and identify sedation or neuraxial complications that require immediate anaesthetic assessment.

  • The patient's request, clinical situation and preferences guide analgesia; there is no requirement to endure a fixed level of pain first.
  • Support, movement, breathing techniques, massage and water can help, and may be combined with pharmacological methods.
  • Inhaled nitrous oxide with oxygen is rapidly adjustable but often provides partial relief and may cause nausea or light-headedness.
  • Intramuscular opioids provide limited labour analgesia and can cause maternal sedation and neonatal respiratory depression.
  • Epidural analgesia is more effective than systemic opioids and requires anaesthetic assessment, appropriate monitoring and a plan for inadequate effect.
  • Remifentanil PCA is restricted to obstetric units with continuous trained one-to-one care, respiratory monitoring and immediately available anaesthetic support.
  • An analgesic plan should be reviewed when labour progresses, the patient changes preference or a new maternal or fetal concern appears.

Key red flags

Inability to remain awake, respiratory depression or desaturation during opioid analgesia requires immediate intervention.

Breathlessness, difficulty speaking, arm weakness or rapidly increasing numbness after an epidural dose raises concern for a high neuraxial block.

Severe hypotension or a new fetal heart abnormality after regional analgesia needs prompt assessment and treatment.

New severe back pain with neurological deficit or bladder dysfunction after neuraxial treatment requires urgent specialist investigation.

Fever with spinal pain, or a severe persistent postpartum headache, warrants assessment rather than routine reassurance.

Investigation priorities

01
Respiratory and sedation assessmentFirst step

Detect systemic opioid effects before ventilation becomes unsafe.

Management branches

Initial and evolving painOffer a range of practical choices

The patient requests pain relief or the current approach is no longer sufficient.

  1. Explain the options available in the current setting and ask which benefits and drawbacks matter most to the patient.
  2. Offer supportive care, comfortable positions, breathing techniques, massage and access to water where suitable, without making these a prerequisite for stronger analgesia.
  3. Consider inhaled nitrous oxide with oxygen, sterile water injections for back pain, or a systemic opioid with an antiemetic as appropriate.
  4. Reassess relief, side effects and the stage of labour, and arrange transfer or anaesthetic review if the patient requests a method unavailable locally.

Key medicines

Nitrous oxide with oxygen, EntonoxUse the premixed 50% nitrous oxide and 50% oxygen gas through a patient-held demand system. Begin inhalation as a contraction starts and stop according to comfort, dizziness or nausea.The patient must remain able to use the device safely. Review impaired consciousness and conditions involving trapped gas spaces or relevant vitamin B12 risk; increasing sedation from other medicines changes the assessment.
Pethidine injectionThe cited UK SmPC obstetric regimen is 50–100 mg intramuscularly or subcutaneously, with a further dose 1–3 hours later if needed, to a maximum of 400 mg in 24 hours. The maternity prescription should select dose and timing after assessment.Give an antiemetic and reassess sedation and breathing before another dose. The product contraindicates severe respiratory depression, severe obstructive airways disease or acute asthma, severe renal or hepatic impairment, and MAOIs taken within the previous two weeks, including moclobemide, selegiline and rasagiline. Review other sedatives and proximity to birth; avoid a bath or pool for two hours after administration and while drowsy.
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Sources and review status4 sources · checked 7 Sept 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 7 Sept 2026; clinical approval remains outstanding.

  • NICE NG235 pain relief and regional analgesia
  • Pethidine injection product characteristics
  • Remifentanil product characteristics
  • NHS pain relief in labour

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom