Obstetric analgesia and anaesthesia

She is 4 cm dilated, in agony, and asking for "the needle in my back". The decision you make in the next two minutes — and the way you explain it — is half the station. Obstetric analgesia is examined relentlessly because it sits where physiology, pharmacology, communication and risk collide, and because the obstetric airway is still the place young women die under anaesthesia. Know the ladder, know the doses, and know the drills.[1][5]

Overview — the analgesia ladder

Labour analgesia is a ladder, and the rungs matter because each trades pain relief against intervention and monitoring. [1][4]

• Non-pharmacological — hydrotherapy, massage, hypnobirthing, positional change, continuous support. Real but modest; never denigrate a woman's choice, but do not pretend it replaces effective analgesia for established labour pain.[1]
• Inhalational — nitrous oxide (Entonox), a 50:50 mix with oxygen. Self-administered via a demand valve. The systematic review position: less effective than epidural, but safe, with few maternal or neonatal side effects, and valued by women who want something that does not tether them to a monitor or a needle.[4]
• Systemic opioid — intramuscular pethidine is the ANZ default. Limited efficacy, maternal sedation and nausea, and neonatal respiratory depression if given close to delivery. Falling out of favour for good reason.[8]
• Remifentanil PCA — intravenous, patient-controlled, short half-life. Halves the rate of epidural conversion compared with pethidine, but demands one-to-one monitoring because it depresses respiration.[3][9]
• Neuraxial — epidural, spinal, combined spinal-epidural. The most effective analgesia available, and the only method that can be extended to surgical anaesthesia for caesarean without a separate procedure.[1]