Clinical overview
Labour pain is among the most severe pain a woman will experience, yet the right analgesic for any given woman is rarely the strongest one — it is the option that matches her physiology, her parity and stage of labour, her medical and obstetric risk profile, her preferences, and, crucially in South Africa, the level of care and the staff and drugs actually available at the place she is birthing. The FCOG(SA) objective is a selection task: you are not asked merely to list modalities, but to weigh options against indications and complications for the woman in front of you. That is a higher-order skill. A registrar who can recite that epidural is "the most effective" but cannot recognise when it is contraindicated, cannot consent for it honestly, or cannot manage a hypotensive crash or a dural puncture, has not met the objective.
The South African reality frames every decision. The National Integrated Maternal and Perinatal Care Guideline (NDoH, 2024) sets the expectation that pain relief is offered, but regional analgesia (epidural) is largely confined to regional and tertiary hospitals with on-site anaesthetic cover; the typical district clinic or community health centre relies on non-pharmacological support, intramuscular opioids, and inhaled nitrous oxide. Knowing this geography — and knowing when inadequate analgesia is itself a reason to refer up a level of care — is part of selecting appropriately. Respectful, autonomy-preserving care (see respectful-care) means the woman's request for pain relief is a legitimate indication in its own right; she does not have to "earn" analgesia by reaching an arbitrary cervical dilatation.
Core knowledge
The neuroanatomy of labour pain
Pain in the first stage arises from uterine contraction and cervical dilatation. It is visceral, poorly localised, and carried by small afferent C-fibres entering the spinal cord at T10–L1. As labour advances into the second stage, somatic pain from distension of the vagina, pelvic floor and perineum is added, transmitted via the pudendal nerve to S2–S4. This anatomy explains why a low blockade (e.g. a pudendal block) covers perineal but not contraction pain, and why neuraxial techniques must cover from roughly T10 down to the sacral roots to abolish both components.
Untreated severe labour pain is not benign. It drives maternal hyperventilation and a catecholamine surge that can reduce uteroplacental perfusion, and it causes maternal exhaustion and distress. These are physiological arguments for analgesia, but they should be presented carefully rather than overstated — standard teaching, not a hard outcome guarantee.
Figure I15.1 — Labour pain pathways explain why neuraxial blockade covers contraction and perineal pain, while pudendal and local infiltration blocks only cover second-stage or repair pain.
The modalities, in ascending intensity
Non-pharmacological measures — continuous one-to-one support, freedom of movement and upright positions, a warm bath/shower, breathing and relaxation techniques, massage, and a calm environment — reduce reported pain and the need for pharmacological analgesia and have essentially no maternal or fetal harm. They are the universal baseline and should never be skipped because "real" analgesia is available. Continuous labour support is one of the best-evidenced interventions in intrapartum care.
Inhaled nitrous oxide and oxygen (typically a 50:50 premixed gas, "Entonox"/"Entanox") is self-administered, fast on and fast off, with no significant effect on the progress of labour or on the neonate when used appropriately. It gives modest, partial relief. Side-effects are light-headedness, nausea and a dry mouth; adequate room ventilation matters for staff exposure. It is widely usable across levels of care and is a sensible first pharmacological step.
Parenteral opioids — classically intramuscular pethidine (the long-standing workhorse in SA public obstetrics) and, where available, morphine — are cheap, need no anaesthetist, and are deliverable at any level. Their limitations are important and examinable. They provide only partial relief (many women describe sedation and "distance from" the pain rather than abolition of it), cause maternal nausea, vomiting and sedation, and cross the placenta, risking neonatal respiratory depression and sedation, especially if given close to delivery. Pethidine's active metabolite norpethidine accumulates with repeated dosing and can cause neonatal neurobehavioural effects; this is standard pharmacology teaching. Naloxone must be immediately available for the neonate. Avoid giving an opioid when delivery is anticipated within the next short window if it can reasonably be deferred.
Regional/neuraxial analgesia — the epidural, and the combined spinal–epidural (CSE) — is the most effective form of labour analgesia and the reference standard against which others are judged. A catheter in the epidural space allows a titratable, continuous low-dose local anaesthetic (e.g. bupivacaine or ropivacaine) combined with a lipophilic opioid (e.g. fentanyl), the opioid allowing the local-anaesthetic concentration to be kept low to preserve motor function ("low-dose"/"mobile" epidural). CSE gives faster onset via the spinal component. This is the option that most often changes a labour from intolerable to manageable, and it is the only modality reliable enough to convert smoothly to surgical anaesthesia for caesarean.
Other regional techniques: a pudendal nerve block (local anaesthetic to the pudendal nerve near the ischial spine) covers perineal/second-stage and instrumental-delivery pain but not contractions; perineal local infiltration covers episiotomy/repair only. These are useful, low-resource adjuncts, particularly for instrumental delivery (see instrumental-delivery) where a neuraxial block is absent.
Assessment
Selection begins with a focused assessment that pairs the woman's needs against the safety screen for each modality.
- The woman's preference and current distress. Ask what relief she wants and explain honestly what each option can and cannot do. Her informed request is a valid indication.
- Stage and likely trajectory of labour. A multipara at 8 cm progressing fast may deliver before an epidural is sited and may be best served by nitrous oxide and support; a primigravida at 4 cm with a long road ahead, or an induced labour, is a strong candidate for early epidural.
- Obstetric indications that favour epidural specifically. Hypertensive disease and pre-eclampsia (blunts the hypertensive response to pain and to delivery), anticipated operative vaginal delivery or trial of labour with higher caesarean likelihood, trial of labour after caesarean (does not mask rupture pain if monitored), multiple pregnancy, breech vaginal birth, and prolonged/induced labour all tilt toward neuraxial analgesia where it is available.
- Contraindications to neuraxial techniques — screen actively:
- Patient refusal and inability to cooperate/position.
- Coagulopathy or therapeutic anticoagulation, and clinically significant thrombocytopenia — the platelet count and timing of any low-molecular-weight heparin must be checked before insertion. Thrombocytopenia is common in pre-eclampsia/HELLP, so check the platelets and coagulation before assuming an epidural is on the table.
- Local sepsis at the insertion site or untreated systemic sepsis/septic shock.
- Hypovolaemia/uncorrected haemorrhage and haemodynamic instability — neuraxial sympathetic blockade in a bleeding woman is dangerous; correct first.
- Raised intracranial pressure and certain fixed-output cardiac lesions warrant senior anaesthetic input.
- For opioids: timing relative to expected delivery (neonatal depression risk), maternal respiratory or sedation concerns, and any contraindication to the specific agent.
- Baseline observations and venous access. IV access, blood pressure and a CTG/auscultation baseline (see fetal-monitoring-methods) should be in place before regional analgesia; continuous electronic fetal monitoring is standard once an epidural is running, given the early risk of hypotension and the dense block masking change.
A simple framework many registrars use:
| Setting | Realistic first-line options |
|---|---|
| Home/community midwife obstetric unit (low risk) | Support, mobilisation, water, breathing; nitrous oxide if stocked |
| District hospital | Above + IM opioid (pethidine); pudendal/perineal local for delivery |
| Regional/tertiary hospital | All of the above plus epidural/CSE with anaesthetic cover |
Management
Building the analgesic plan
Layer the modalities. Start every labour with continuous support and non-pharmacological measures. Offer nitrous oxide for partial relief and for the woman who wants to stay mobile and self-control her analgesia. Use a parenteral opioid where neuraxial analgesia is unavailable or unwanted, the woman has no contraindication, and delivery is not imminent — and ensure neonatal naloxone is to hand. Escalate to epidural/CSE for the woman who wants the most effective relief, has an obstetric indication, or whose pain is not controlled — provided there is no contraindication and anaesthetic cover exists. Where a level of care cannot provide the analgesia a woman clinically needs, referral up a level is part of the management, planned in good time per the SA Maternity Guideline pathways.
Figure I15.2 — Stepwise selection of labour analgesia by need, stage, obstetric risk, contraindications and South African level-of-care resources.
Siting and running an epidural — and its complications
The anaesthetist sites the catheter under aseptic technique with the woman positioned and monitored, after IV access. Once dosed, vigilant monitoring is mandatory: frequent blood pressure (sympathetic blockade causes vasodilatation), block height, motor function, and continuous fetal monitoring. Examinable complications, and their management:
- Maternal hypotension (the commonest early problem) → can cause fetal bradycardia. Manage with left-lateral/uterine displacement, IV fluid, and a vasopressor (e.g. phenylephrine or ephedrine), and check the fetal heart.
- Inadequate or patchy/one-sided block → reposition, top-up, or replace the catheter.
- Accidental dural puncture → post-dural-puncture headache — postural, frontal/occipital; managed conservatively first (analgesia, hydration, caffeine) and with an epidural blood patch if severe/persistent. Counsel as part of consent.
- High/total spinal block — excessive cephalad spread causing hypotension, respiratory difficulty and, at the extreme, apnoea and collapse: this is an emergency requiring airway support/ventilation, circulatory support and a call for senior anaesthetic help.
- Local anaesthetic systemic toxicity (LAST) — from inadvertent intravascular injection: peri-oral tingling and CNS excitation progressing to seizures, then cardiovascular collapse. This is a drill, not a discussion.
- Other: pruritus and urinary retention (from neuraxial opioid), maternal pyrexia, and transient effects on the urge/ability to push. Epidural is not an independent indication for caesarean; it can modestly prolong the second stage and is associated with more instrumental deliveries in some data — counsel honestly without overstating.
Emergency drills — make them unmistakable
Local anaesthetic systemic toxicity (LAST):
- STOP injecting the local anaesthetic immediately. Call for help and the cardiac-arrest/anaesthetic team.
- Airway, breathing, circulation — give 100% oxygen, secure the airway, ventilate.
- Control seizures (benzodiazepine).
- Give intravenous lipid emulsion ("Intralipid"/20% lipid) per the LAST protocol — this is the specific antidote; know where it is kept on your unit.
- If cardiac arrest: start CPR with left-uterine displacement, follow ACLS modified for pregnancy, and if there is no return of circulation, prepare for perimortem caesarean (aim within ~5 minutes of arrest) to aid maternal resuscitation (see resuscitation-in-pregnancy).
Epidural-associated hypotension with fetal bradycardia:
- Left-lateral tilt / manual uterine displacement, stop any oxytocin.
- Rapid IV crystalloid bolus and vasopressor (phenylephrine/ephedrine).
- Give oxygen, recheck blood pressure and the fetal heart.
- Exclude other causes of bradycardia (cord prolapse, abruption, rupture) and escalate.
Neonatal opioid depression at birth: anticipate it if an opioid was given near delivery — have the resuscitaire ready, support ventilation, and give neonatal naloxone per the resuscitation protocol while ventilating (see neonatal-resuscitation and initiation-of-respiration).
Figure I15.3 — Emergency drills for epidural hypotension with fetal bradycardia, LAST, high or total spinal block and neonatal opioid depression.
Red flags / pitfalls
- Giving an IM opioid close to delivery. The classic error: a labouring multipara gets pethidine and delivers a flat, sedated baby an hour later. Anticipate progress; have naloxone ready.
- Skipping the platelet count/coagulation screen before an epidural, especially in pre-eclampsia — thrombocytopenia and coagulopathy are real contraindications and an epidural haematoma is catastrophic.
- Not correcting hypovolaemia first. Siting a neuraxial block in a bleeding or under-resuscitated woman invites cardiovascular collapse.
- Treating an epidural-related fetal bradycardia as "fetal distress for caesarean" before correcting maternal hypotension with tilt, fluid and vasopressor — many recover.
- Forgetting LAST. If a woman convulses or collapses soon after an epidural top-up, think LAST and get the lipid emulsion — do not just label it eclampsia.
- Offering analgesia conditional on cervical dilatation. Pain relief is offered on need and request, not "earned"; withholding it is disrespectful care.
- Promising an epidural where there is no anaesthetic cover. Be honest about what your level of care can deliver and refer in good time rather than at crisis point.
- Overstating epidural risks (the "it leads to caesarean" myth) or understating them. Consent honestly: epidural does not cause caesarean, but it is associated with more instrumental births and a slightly longer second stage in some data, and carries the specific neuraxial complications above.
- Neglecting non-pharmacological support because pharmacological options exist — continuous support reduces analgesic need and improves experience.
Evidence anchors
- South African National Integrated Maternal and Perinatal Care Guideline (NDoH, 2024) — the SA source of truth: what analgesia is expected at each level of care, opioid use, and referral pathways.
- South African EML — Hospital Level (Adults), current edition — for the available agents (e.g. pethidine, morphine, local anaesthetics, naloxone, lipid emulsion); confirm formulary specifics against the current list.
- NICE NG235 — Intrapartum care (2023) — care of healthy women and babies in labour, including pain-relief options (non-pharmacological, inhaled, parenteral opioids, regional) and the principle of offering analgesia on request.
- NICE NG229 — Fetal monitoring in labour (2022) — informs continuous monitoring once regional analgesia is running and after opioid/epidural-related changes.
- WHO Labour Care Guide (2020) — supportive intrapartum care framework into which analgesia decisions fit.
- Saving Mothers / NCCEMD report (latest triennium) — anaesthesia-related maternal deaths are a recognised avoidable category in SA; selection and safe conduct of analgesia/anaesthesia is a maternal-safety issue.
Several pharmacology and complication-management details above (specific drug examples such as bupivacaine/ropivacaine + fentanyl epidural mixtures, pethidine/norpethidine neonatal effects, phenylephrine/ephedrine for hypotension, lipid-emulsion antidote for LAST, and the post-dural-puncture-headache/blood-patch pathway) are stated as standard anaesthetic/obstetric teaching; they are not line-itemed in the verified-sources list, so confirm exact doses, concentrations and local LAST/PDPH protocols against your institutional anaesthetic guideline and the current SA EML before prescribing.