This information has been prepared by Australian and New Zealand College of Anaesthetists (ANZCA). It is only a guide and should not replace information supplied by your anaesthetist. If you have any questions about your anaesthesia, please speak with your treating specialist.
Labour is among the most painful human experiences. The cause of labour pain is multifactorial and includes stretching of the cervix during dilatation in the first stage of labour, and stretching of the vagina and perineum in the second stage of labour. Anaesthetists play an important role in providing pain relief and facilitating delivery of the baby. A common form of pain relief for labour is by epidural. For further information see epidural and childbirth.
It is advisable for pregnant women to discuss the methods of pain relief with the midwife, obstetrician or anaesthetist well in advance of their labour.
Should pregnant women need to have their babies delivered by caesarean section, (an operation where the baby is delivered via an incision in the abdomen) which may be advised or required for medical reasons, the anaesthetist will provide the most appropriate form of anaesthesia. This may be either regional anaesthesia in the form of a spinal block, an epidural block, or a combined spinal-epidural block, or general anaesthesia.
Epidurals are the most effective method of pain relief for labour and require the services of an anesthetist. Some pain relief alternatives, such as medications given by injection, do not require the services of an anaesthetist but will be prescribed by a doctor.
Download the ANZCA factsheet on pain relief and having a baby.
Nitrous oxide
A mixture of nitrous oxide (N20) with oxygen can be self-administered by a woman who is in labour. About 85 per cent of women find it helpful, although few find it adequate as the only means of pain relief. Nitrous oxide is an analgesic and is relatively safe during labour when mixed with oxygen.
Epidural anaesthesia for pain relief
Epidural and spinal analgesia/anaesthesia (also called central neuraxial analgesia/anaesthesia), where local anaesthetic with or without opioid is administered around the outer coverings of the spinal cord or into the fluid bathing the spinal cord, is the most effective relief available for labour pain.
Epidural and spinal anaesthesia may be performed with patients in the sitting position or lying on their side depending on the anaesthetist's preference. After washing the back with antiseptic solution local anaesthetic is injected under the skin to reduce discomfort that may be felt from passage of the epidural needle.
Patients are positioned with a curved back posture, typically described as making the shape of the Sydney Harbour Bridge or an angry cat. By placing the chin on to the chest and dropping the shoulders, the space between the vertebrae increases to allow passage of the epidural needle. A fine plastic tube known as an epidural catheter may be threaded through the needle, after which the needle is removed.
The epidural catheter sits in the epidural space outside the spinal cord and the spinal fluid. Local anaesthetics can be administered via this catheter to block transmission of pain along the nerves coming from the womb and cervix. Medications may be administered as a continual flow through the epidural catheter throughout the labour or by a midwife injecting the prescribed dose into the epidural catheter.
The time taken to perform the procedure depends on issues such as the shape and curve of the patient's spine and whether the patient is overweight. It may take between five and 30 minutes to perform, with the onset of pain relief starting within five minutes of the patient receiving the local anaesthetic.
For further information about side effects and complications of epidural anaesthesia, see the ANZCA page on epidurals and childbirth
