⚡ Anaphylaxis in Pregnancy
IN REVIEWPENDING CLINICAL VERIFICATIONTIME-CRITICAL PROTOCOL
1 RECOGNIZE
- Rapid airway, breathing or circulation compromise after a likely trigger; skin/mucosal changes may be absent.
- Wheeze/stridor, swelling, hypotension or collapse demands immediate treatment; do not wait for rash or a tryptase result.
2 CALL FOR HELP
- Call resuscitation/anaesthesia and senior obstetric team; bring IM adrenaline, oxygen, IV fluids and airway equipment.
3 IMMEDIATE ACTION
- Stop the suspected trigger/infusion and give IM adrenaline 500 micrograms immediately; repeat after 5 min for persistent airway/breathing/circulation problems. The complete concentration/volume is below.
- Position appropriately: do not allow standing/sudden sitting; in later pregnancy use left-lateral positioning or manual uterine displacement if supine resuscitation is required.
- Give oxygen, obtain IV access and support the airway early. Adult shock may need rapid 500–1000 mL crystalloid boluses with reassessment; monitor closely and individualise for cardiac/obstetric physiology.
- Persistent features after TWO appropriate IM doses: expert-led refractory-anaphylaxis treatment with a monitored IV adrenaline infusion. Do not give IV boluses of the IM-strength solution.
- Antihistamines do not treat airway/breathing/circulation compromise. Routine hydrocortisone is not first-line emergency treatment; neither should delay adrenaline or fluids.
Drug doses & preparation
Choose the regimen for the stated indication. Alternatives are not instructions to give every medicine. Check prior doses, contraindications, concentration and the response before repeating.
Adrenaline — anaphylaxisResuscitation Council UKchecked
Dose500 micrograms (0.5 mg)
RouteIM into the anterolateral mid-thigh
FrequencyRepeat after 5 min if airway/breathing/circulation problems persist
DurationContinue emergency reassessment; refractory reaction after 2 appropriate IM doses needs expert IV-infusion/critical-care support
Preparation1 mg/mL ampoule: 0.5 mL = 500 micrograms IM. Use mg/mL labels rather than ratio alone. NEVER give this IM-strength dose as an IV bolus
Max doseNo fixed total IM-dose ceiling while life-threatening features persist; repeat every 5 min and escalate
- Indication: Airway/breathing/circulation compromise from suspected anaphylaxis, including pregnancy
Monitoring
- Airway, breathing, BP/pulse, ECG and SpO2; pregnancy positioning and fetal assessment after maternal resuscitation
Contraindications: No absolute contraindication to IM adrenaline in life-threatening anaphylaxis; do not withhold because of pregnancy · IV adrenaline requires an experienced clinician and monitored infusion; antihistamines/steroids do not replace adrenaline
Adrenaline — refractory anaphylaxis infusionResuscitation Council UKchecked
DoseStart 0.5–1 mL/kg/hour of the 10-microgram/mL solution according to severity, then titrate to response
RouteIV infusion pump
FrequencyContinuous with immediate response-based titration
DurationUntil the reaction resolves and a supervised weaning/observation plan is established
PreparationMake 1 mg adrenaline up to FINAL 100 mL sodium chloride 0.9% =10 micrograms/mL. Use a dedicated labelled line and pump; do not piggyback where another infusion can cause an adrenaline bolus.
Max doseNo fixed universal rate ceiling; senior titration and invasive/continuous monitoring for refractory shock
- Indication: Persistent airway/breathing/circulation compromise after two appropriate IM doses; experienced critical-care/anaesthetic staff only
- At 70 kg, 0.5 mL/kg/hour =35 mL/hour =350 micrograms/hour (about 5.8 micrograms/min). The higher initial rate is chosen only by the experienced team.
Monitoring
- Continuous ECG, frequent/continuous BP, pulse, oxygenation and clinical response; inspect the IV line
- Continue IM adrenaline every 5 min while arranging the expert infusion if compromise persists; do not delay initial IM treatment
Contraindications: Do not start an unmonitored IV infusion or give IV boluses of the IM-strength solution · Tachyarrhythmia/marked hypertension needs immediate dose and line assessment
4 INVESTIGATIONS (never delaying treatment)
- Monitor ECG, BP, pulse, SpO2 and response continuously. Mast-cell tryptase sampling after initial stabilisation should not delay treatment; arrange timed samples and later baseline under the allergy pathway.
5 DEFINITIVE MANAGEMENT
- Reassess after every intervention; titrate expert infusion and fluid support for refractory shock. Prepare advanced airway/ventilation if airway oedema or exhaustion progresses.
- Assess the fetus after maternal resuscitation; restoring maternal oxygenation/perfusion is the immediate priority.
- Choose observation duration by reaction severity and treatment: prolonged observation is required after multiple adrenaline doses, severe respiratory compromise or other high-risk features; do not use a universal 6 h discharge rule.
6 ESCALATION
- Two IM doses with persistent compromise, airway deterioration or shock: critical care and monitored IV infusion immediately.
7 POST-EVENT CARE
- Record trigger, drug names/doses/timing and severity; provide clear allergy documentation and specialist referral.
- Before discharge give emergency advice, an appropriate adrenaline-auto-injector plan/training and follow-up arrangements.
Admission & discharge after the acute event
Care setting: Emergency treatment and risk-stratified observation before any discharge
Admission/discharge guidance checked 2026-10-18 against the linked sources. This is a clinical checklist for an individual decision, not an automatic discharge order.
When admission or continued hospital care is needed
- Admit/continue monitored care for persistent symptoms, repeated adrenaline needs, severe respiratory compromise, ongoing allergen absorption, comorbidity or poor emergency access.
- Pregnancy needs obstetric/fetal assessment in addition to the general anaphylaxis observation decision.
When clinic, day care or home care may be suitable
- Acute anaphylaxis needs emergency care. Home care is considered only after complete recovery and a senior assessment of recurrence risk.
Before going home
- RCUK: selected fast-track discharge after 2 hours from symptom resolution requires prompt response to one early adrenaline dose, complete resolution, available auto-injectors with training and adequate supervision.
- Observe at least 6 hours after resolution if two IM doses were needed or there was a previous biphasic reaction; at least 12 hours for severe reactions (>2 doses), severe asthma/respiratory compromise, continuing allergen absorption or difficult access/night-time safety concerns. Longer admission may be needed.
Discharge medicines and treatment changes
- Prescribe/supply adrenaline auto-injectors when indicated, with device-specific training and two available devices under the RCUK/NICE pathway. Do not replace IM adrenaline with antihistamine-only advice.
Tests, pending results and their reviewer
- Record likely trigger, treatment/dose times, observation duration and any tryptase/allergy investigation plan.
Home care and counselling
- Give a written emergency action plan, trigger avoidance, biphasic-reaction warning and instructions to use the prescribed auto-injector and summon emergency help.
Follow-up: when and what to review
| When | Action / responsible service |
|---|---|
Before discharge | Confirm practical device access/training and a safe supervision/transport plan. |
At the booked specialist allergy review | Investigate the trigger and confirm prevention/rescue plans; add obstetric follow-up when pregnant. |
Return urgently
- Recurrent breathing/throat symptoms, collapse or rapidly returning systemic symptoms requires immediate rescue action and emergency help.
Open the complete discharge checklist →
Sources for this plan:
Sources
Resuscitation Council UKcheckedResuscitation Council UKcheckedResuscitation Council UK · May 2021 guidelinecheckedNICE · NG194, recommendationscheckedIndia MoHFW / NHM · LaQshya district-hospital SOP, linked editioncheckedWHO · 2022 official recommendation summarycheckedRCOG · Current public recovery informationcheckedNICE · CG50, recommendationschecked