Note that this advice is general in nature and if you have specific questions please consult your specialist.
Questions were answered by Dr Alister Ooi a registered anesthesiologist and member of the Australian and New Zealand College of Anesthetists (ANZCA).
This week, I’ll discuss epidurals. Epidurals are generally considered to be the most effective form of pain relief available during labour. Most of the other forms of pain relief discussed in last week’s post are provided through your midwife and the obstetric team on the labour ward. However, for an epidural, an anaesthetist, like myself, becomes involved.
What is it?
An epidural involves an injection into the lower part of your back.The aim is to put a thin, sterile tube in the ‘epidural space’ an area behind the lower spinal nerves.This plastic tube allows local anaesthetic and other pain medicines to be injected into the epidural space in both one off injections and also continuously.The local anaesthetic numbs the nerves from the lower part of the spinal cord which supply feeling and pain to your uterus and pelvic area.This reduces the pain from contraction and delivery.
A well working epidural provides the most effective pain relief available during labour. There is also minimal direct effect on your baby, as the local anaesthetic acts directly on the spinal nerves in the epidural space and does not cross the placenta (unlike opioid pain relief given directly into the vein for example). Finally, if there is any need for an instrumental delivery or to come to the operating theatre (e.g. for a Caesarean section or for management of any complications after delivery) the epidural can be ‘topped up’ with a stronger dose of local anaesthetic without any further needle injections or a general anaesthetic being required.
Epidurals are very safe.They are performed in thousands of women each year around the world for pain relief during labour.They are also used in many other surgical procedures. However, as with any procedure there are some risks. The serious risks include bleeding or infection around the lower spinal cord, which may lead to injury to the nerves supplying the legs. Permanent injury is extremely rare.
We take several precautions to minimise these risks. We use “aseptic technique” when we insert the epidural.You will notice your anaesthetist washing their hands (‘scrubbing’) prior to the procedure and wearing a sterile gown and gloves during the epidural placement. We also check blood tests before we insert an epidural, especially if the woman is at a higher than usual risk of bleeding. In the UK, a study investigated complications of epidurals and estimated the rate of permanent nerve injury from epidurals to be between 1 in 100,000 to 200,000 – i.e. very, very rare.
Less serious risks include causing a headache after the epidural (usually a day or so later), which can be treated in several ways. Also, occasionally the epidural may not be effective straight away. However, usually with some extra dosing of local anaesthetic, adjustment of the epidural plastic tube or occasionally re-insertion of the epidural, we can get it working well. Your blood pressure may drop slightly after an epidural.This is due to relaxation of the blood vessels in the same area that is numbed by the local anaesthetic. Your midwife will check your blood pressure more frequently for the initial period after the epidural is inserted to monitor closely for this.
The nerves supplying the uterus and birth canal are in the same part of the spinal cord as the bladder. As a result, the nerves to the bladder can also become ‘numb’, making it more difficult to pass urine. Usually, after an epidural is inserted a urinary catheter is also placed into the bladder to allow urine to drain normally. Like the epidural, this usually remains until just after delivery.
Common questions about epidurals
1.How long does it take to work? How long does it last?
Once the anaesthetist arrives, an epidural typically takes about 15-20 minutes to insert. Be aware that the anaesthetist is also responsible for the operating theatre.This means that when you ask for an epidural, the anaesthetist may not be able to come to put it in right away, particularly if there is another operation taking place at the same time. Once injected, the initial dose of local anaesthetic can take up to about 10 minutes to take effect. I usually tell mums that the next set of contractions after the epidural goes in are likely to be still painful; then they should start to improve after that.
inserted, the epidural is connected to a pump which continues to inject local
anaesthetic. This is either done automatically or is controlled by a button
which you press when you feel you need increased pain relief. As a result, the
epidural continues to work all the way until you deliver your baby, no matter
how long your labour takes. It is then removed after delivery when it is no
2.Will I feel any pain? Can I move? Can I push?
The local anaesthetic used in epidurals for pain relief during labour is relatively dilute. This is because the aim is to provide pain relief from contractions but not to make your legs numb and weak - that you can still push for the birth. Like other forms of pain relief, the idea is reduce the pain right down to a level which is more manageable for you. In particular, the sensation of pressure in the pelvis and birth canal can be difficult to remove, particularly while maintaining movement in the legs.
However, if you proceed to have a Caesarean section or other surgical procedure the dose of local anaesthetic used is much stronger to provide anaesthesia for surgery (i.e. total numbness including an inability to move legs).
3.Does it increase the rate of ___________?
a.Caesarean section rate
i.There have been many studies investigating whether epidurals change the method of delivery. When combined these studies clearly show that epidurals do not increase the risk of Caesarean section.
b.Duration of labour and rate of instrumental delivery
i.Several studies have shown a small prolongation of the second stage of labour (the time from when the cervix is fully dilated to when your baby is born) and an increase in rate of instrumental deliveries (vaginal deliveries assisted by forceps or vacuum). It might be that women with complicated, painful and prolonged labour request epidurals more frequently, which may also be a population who require a higher rate of instrumental deliveries.
i.Back pain is unfortunately very common after childbirth due to the effect of carrying an increasingly heavy baby with your lower back for several months. Up to 50% of women report some back pain at 6 months after delivery. However, several studies investigating the topic have confirmed that epidurals do not increase the occurrence of back pain after having a baby.
In summary, epidural injections provide probably the most effective pain relief during labour and delivery.Overall it is very safe, with the risk of complications being extremely rare. I hope this information has been helpful in guiding your decision regarding pain relief during labour. I would encourage you to keep an open mind and allow some flexibility in your plans during labour – by far the most important thing is that you have a healthy, happy baby at the end of it. For any fathers/partners reading this - fully support your partner regarding whatever decision she makes about pain relief during labour – she’s the one going through it!