Analgesia in Labour for Undergraduates

1. Analgesia in Labour for Undergraduates Max Brinsmead PhD FRANZCOG September 2012

2. This Talk • Pain in Labour • Who gets it and how bad • Pain & satisfaction with the birth experience • The role of endorphins • Non – Pharmacological Options • 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

3. This Talk (2) • Pharmacological Options • Nitrous oxide by inhalation • Narcotics • Advantages and Disadvantages • Choice of drug, dose and route • Sterile Water by Injected Papule • 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)

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

5. Pain in Labour (2) • Patient’s rating of pain in labour and satisfaction with analgesia VARIES according to when they are studied: • 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

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

7. Position in Labour • 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

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

9. Massage & Therapeutic Touch • 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

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

11. Acupuncture and Acupressure • 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

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

13. Transcutaneous Electrical Nerve Stimulation (TENS) • 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

14. Aromatherapy • 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

15. Labouring in Water • 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” • 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

16. Antenatal Education • Reported pain in labour is influenced by a patient’s expectations • So preparation for childbirth is one important component of antenatal care • 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

17. Role of a Support Person • Rates of spontaneous birth are possibly increased... • and length of labour is reduced by • 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

18. Nitrous Oxide by Inhalation (Entonox) • 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

19. Narcotic Analgesics • 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 2nd stage of labour • Should always be administered with an anti emetic drug • Which actually enhances its analgesic effects • The main problem is its potential to cause respiratory depression in the neonate • And a reluctance to feed which can last several days

20. Neonatal Depression from Narcotics • 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

21. Neonatal Depression from Narcotics (2) • 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

22. Intrapartum Epidural Anaesthesia • 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 pH) • Reduces maternal blood pressure • Useful if the woman is pre eclamptic • Will reduce the risk of eclampsia

23. The Cons of Epidural Anaesthesia • 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 • Reduces maternal mobility • Requires IV access and fetal monitoring • Particularly when oxytocin augmentation is used

24. Side Effects & Risks of Epidural Anaesthesia • Maternal hypotension • Shivering • Reduced capacity for mobilisation in labour • Risk of dural puncture and severe headache about 1% • May require a “blood patch” • Bladder function compromised • Catheter commonly required • May cause some incontinence for some weeks after • Epidural haematoma, abscess & nerve damage very rare • Does NOT cause long-term backache