Analgesia in Labour for Undergraduates Max Brinsmead MB

Analgesia in Labour for Undergraduates Max Brinsmead MB BS Ph. D April 2019

This Talk n n Pain in Labour – – – Who gets it and how bad Pain & satisfaction with the birth experience The role of endorphins – – – – – Position for labour Breathing and relaxation Massage and Touch Distraction and Music Acupuncture and Hypnosis Transcutaneous Electrical Nerve Stimulation (TENS) Other methods e. g. Aromatherapy Labouring in Water The role of antenatal education The role of a support person Non – Pharmacological Options

This Talk (2) n Pharmacological Options – Nitrous oxide by inhalation – Narcotics n n Advantages and Disadvantages Choice of drug, dose and route – Sterile Water by Injected Papule n Anaesthetic Techniques – Epidural Anaesthesia – Spinal (talk to an anaesthetist about this) – Paracervical Block (no longer practised) – Pudendal Block (talk to an obstetric registrar) – Perineal infiltration (not covered in this talk)

Pain in Labour n n 80 – 90% of women describe their pain in labour as “very severe” or “intolerable” Pain does not correlate with. . . – Age – Education – Social class n Satisfaction with “the birth experience” does not correlate either with the pain of labour or with satisfaction with analgesia

Pain in Labour (2) n Patient’s rating of pain in labour and satisfaction with analgesia VARIES according to when they are studied: – – – n In labour Immediately postpartum Several weeks postpartum This is due to the amnesic effects of labour and is presumably mediated by endorphins – – – “Nature’s opiates” Which are elevated by pregnancy and. . . Highest in labour

Pain in Labour (3) n Patient’s reaction to the pain of labour will vary according to her expectations – Personal – Cultural n The continuum ranges from. . . – “No woman needs to suffer” – Therefore it is our role to remove it completely n To. . . – It is “natural” or “ordained” – And a “part of the experience” n Most women are somewhere in between

Position in Labour n n n Pain is greatest when the patient lies on her back Patients should be encouraged to adopt a position of comfort There is evidence that remaining upright and mobile improves labour efficiency

Breathing & Relaxation n Limited studies show benefit Harmless to mothers and babies Provided that prolonged breath-holding is avoided

Massage & Therapeutic Touch n n Has been studied by RCT Shown to reduce the pain of labour Reduces anxiety and stress And resulted in better mood and less postnatal depression in one study

Distraction & Music n n n Has been studied by one RCT Reduces both the pain and distress from pain Harmless to mothers and babies

Acupuncture and Acupressure n n Has been studied in 4 RCTs Reduces the need for pharmacological pain relief and epidural anaesthesia Reduces the need for augmentation of contractions But not the rate of spontaneous birth

Hypnosis n n n Has been studied in 5 RCTs Reduces the need for pharmacological pain relief And the need for augmentation of contractions

Transcutaneous Electrical Nerve Stimulation (TENS) n n n Has been studied in 10 RCTs None showed any reduction in pain or use of further analgesia Some actually showed an increase in pain scores

Aromatherapy n n n Has been studied in one RCT Found no effect on pain or the need for other analgesia And no effect on the rate of spontaneous birth

Labouring in Water n Studies consistently show that women who have access to water (bath or shower) resort to epidural anaesthesia less frequently – Please note that this does not mean “water births” n Does not affect any other outcome. . . – – – Length of labour Rate of SVD Infant outcomes (Apgars etc) Maternal trauma (to the perineum) Infant or maternal infection

Antenatal Education n Reported pain in labour is influenced by a patient’s expectations – So preparation for childbirth is one important component of antenatal care n However antenatal education does not influence. . . – – – The use of analgesia in labour Length of labour Rate of SVD, assisted birth & need for Caesarean Infant outcomes (Apgars etc) Any measure of maternal outcome With the exception of satisfaction if the education is provided by the same person who provides intrapartum care

Role of a Support Person n Rates of spontaneous birth are possibly increased. . . – and length of labour is reduced by n n n One to one care from an empathetic person This can be provided by a female companion or “doula” Whether this role can be taken by a patient’s male partner has not be confirmed

Nitrous Oxide by Inhalation (Entonox) n n n n Is a weak analgesic agent That “takes the edge off” the pain of labour Rapidly effective and rapidly excreted Can be used anywhere (including in water) Has no effect on the progress of labour Causes dizziness/light headedness in 5 – 36% Success in its use is all about timing And this requires a little practice

Narcotic Analgesics n n Intensively used and studied for >50 years But there are only a few placebo-controlled RCTs Is a relatively poor analgesic agent when compared to epidural anaesthesia Causes nausea and drowsiness in women – This can interfere with her ability to cooperate in the 2 nd stage of labour n Should always be administered with an anti emetic drug – Which actually enhances its analgesic effects n The main problem is its potential to cause respiratory depression in the neonate – And a reluctance to feed which can last several days

Neonatal Depression from Narcotics n n n n Depends on maternal metabolism of the drug And this varies from woman to woman But the effect is “dose related” and. . . Because the breakdown metabolites of Pethidine are also a respiratory depressant in the neonate The greatest potential for harm comes from repeated doses Whilst the effect can be totally reversed by Naloxone. . . This drug is often misused in neonatal resuscitation & has not been shown to be effective by RCT

Neonatal Depression from Narcotics (2) n n n Because early studies suggested that the transplacental passage of narcotics is greatest in the first 2 hours after maternal administration Most midwifery and obstetric texts counsel against their use if delivery is expected within 2 hours However, because of the wide individual variation in metabolism. . . It is my view that no woman should be denied her FIRST dose of a narcotic at any stage in labour Route may be important – IV for quick effect

Intrapartum Epidural Anaesthesia n n The most effective form of pain relief available Modern agents that limit motor block and with the addition of a narcotic by continuous infusion gives the best results There is evidence that there is improved placental function (gas exchange and cord p. H) Reduces maternal blood pressure – Useful if the woman is pre eclamptic – Will reduce the risk of eclampsia

The Cons of Epidural Anaesthesia n n n Requires a skilled anaesthetic service There are side effects and some risks It lengthens the second stage of labour – And the need for assisted delivery – But should not increase the requirement for CS n n Reduces maternal mobility Requires IV access and fetal monitoring – Particularly when oxytocin augmentation is used

Side Effects & Risks of Epidural Anaesthesia n n n Maternal hypotension Shivering Reduced capacity for mobilisation in labour Risk of dural puncture and severe headache about Bladder function compromised – Catheter commonly required – May cause some incontinence for some weeks after n n Epidural haematoma, abscess & nerve damage very rare Does NOT cause long-term backache

Rare Complications of Epidural n n n n Accidental dural tap n n n Rate depends on operator experience (0. 5 – 1%) At least 50% associated with severe headache And 25 – 30 % require a blood patch n Total paralysis & profound CVS collapse reverses over time n Platelet count desirable in at-risk patients e. g. pre eclampsia n n Catheter site infection Meningitis Epidural abscess Meticulous site care required and timely removal Accidental intravenous injection of agent Accidental spinal block Epidural haematoma Infection Neurological injury It is very difficult to get incidence rates for the above rare outcomes Lost catheter tip

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