Obstetric Anaesthesia

Dr Paul Goonan - Obstetric Anaesthesia

Labour is among one of the most painful human experiences. Just as every baby is unique, every labour is also very different. No matter how well planned you would like your baby’s birth to be, many babies forget to follow that plan and will instead do things their own way.  Some women will experience a short labour and fast birth whilst others may have a long intense labour with a prolonged birth requiring intervention. For this reason, it’s important that you keep an open mind with regards to the various choices of pain relief that are available to you.

Take time to learn about the different analgesia options and speak to your obstetrician so that you are informed and prepared for whatever eventuates.

What is an Epidural?

Epidurals are an extremely effective form of pain relief available during labour. In Australia, all regional anaesthesia such as epidurals and spinals, are inserted by Specialist Anaesthetists and are used in almost one third of labouring women. Epidurals are especially useful when pain has not been adequately relieved by other methods such as TENS, Entonox (gas) and Pethidine. Other situations when an epidural may be useful:

  • When a forceps, vacuum or Caesarean delivery is likely.
  • To lower the mothers’ blood pressure if it becomes high
  • Breech deliveries
  • Multiple birth deliveries

 

How is an Epidural Inserted?

  • Prior to inserting an epidural, your Anaesthetist will assess you and discuss the epidural with you. He will talk to you about the benefits of an epidural as well as the potential side effects. It is important that you research pain relief options earlier in your pregnancy.
  • If you don’t already have one, an intravenous (IV) cannula will generally be placed into one of the veins in the back of your hand. This is so you can be given IV fluids (this can also be used to give medication to increase the speed of your labour or if you are feeling sick).
  • You will then get into the position for the epidural to be inserted. This will either be sitting forward with your legs hanging over the side of the bed or lying curled up on your side.
  • Your Anaesthetist will examine your back for the insertion point and then clean your back with an antiseptic.
  • Your Anaesthetist will then inject some local anaesthetic into your skin in order to lessen any discomfort.
  • The epidural needle is inserted into the epidural space, which is located near the spinal cord and backbone. Some women say they feel a dull pressure which is usually not painful. This is when it is really important for you to keep still. Your anaesthetist has to be careful to avoid puncturing the bag of fluid that surrounds your spinal cord, as this may give you a headache afterwards.
  • If you have a contraction during insertion of the needle you should stay very still and the Anaesthetist will wait until the contraction is finished before proceeding.
  • Once the epidural catheter is in the correct place, the needle is removed leaving only the thin plastic catheter which is firmly secured to your back.
  • Pain relieving medication can now be prescribed by your Anaesthetist and given through the epidural catheter.
  • It usually takes around 15 to 20 minutes for the medication to give relief.
  • Once the epidural medication is started, your Midwife or Anaesthetist will take your blood pressure regularly.
  • The Anaesthetist will also check that the pain relief medication is working on the right nerves. This is often done by touching your leg and tummy with a small block of ice and asking how cold it feels.

Epidural Medication

The pain relieving medication given via the epidural comes in several different strengths. Most women will be started on a lower strength medication. This medication will generally stop the pain of labour whilst still allowing the patient the sensation of touch and muscle strength.

However, just as all women are different, some may need to have a stronger medication to control the pain of contractions and labour. A stronger medication may do this effectively yet result in weakness of the legs, numbness and pins and needles.

Your Anaesthetist will assess your needs and prescribe the medication that is appropriate to your individual needs and circumstances.

Epidural Top-Ups

Once your Anaesthetist has the epidural up and running it will be necessary, in most cases, to give a repeat dose of the pain relieving medication every 1-2 hours. This will be done in consultation with your midwife and Obstetrician and is dependent on the progress of your labour.

Epidural for Caesarean Section

If you've had an epidural inserted for labour and it has been providing you with good pain relief from contractions, then it is likely that this can be topped-up with different anaesthetic and pain relieving drugs, in order to provide anaesthesia for a caesarean section. Before an epidural for labour is used for a caesarean section, your Anaesthetist will thoroughly assess that you have a successful block. At times, it may be necessary for some patients to have an injection known as a spinal anaesthetic in addition to the epidural infusion. This will also be thoroughly assessed by your Anaesthetist to ensure that you are painfree prior to surgery.

Side Effects of Epidurals

It is important to remember that epidurals in labour and childbirth are very safe. However, as with any other medical procedure, epidurals have potential complications and side effects. For additional information on the rates of side effects from epidurals please click here. You should consider these side effects as well as the benefits of epidural analgesia. Please discuss any concerns or questions with your Anaesthetist prior to inserting the epidural.

More Common

  • Low blood pressure is the most common side effect associated with having an epidural. This is because the medication given via the epidural, affects the nerves that go to your blood vessels, which causes a fall in blood pressure - your blood pressure will be closely monitored. Fluids and/or medication may be given to treat the blood pressure.
  • Lightheadedness and dizziness - generally as a result of a lower blood pressure.
  • Nausea and vomiting - due also as a result of a lower blood pressure.
  • Temporary leg weakness or heaviness - this is due to the effect of the local anaesthetic on nerves which control leg movement. The effect is temporary and wears off within several hours
  • Urinary retention - Generally speaking, you will require a urinary catheter after the epidural is placed. A catheter will be inserted into your bladder to allow urine to drain away. Your bladder control will return to normal as soon as the epidural wears off.
  • Shivering - is very common and is due to the epidural medication. It is of no medical consequence and no treatment is needed. Shivering is temporary and will wear off within several hours.
  • Itchy skin - is also of no medical consequence and is generally treated conservatively.

Less Common

  • Post-dural puncture headaches - caused when the lining of your spinal cord (dura) is accidentally punctured during insertion of the epidural. When the dura is punctured, the fluid inside will leak out, resulting in a fall in the pressure of your brain and spinal cord. The decrease in pressure can lead to a persistent and severe headache. The headache symptoms will resolve when the puncture hole is sealed. Whilst most headache symptoms will settle in a few days, occasionally there may be a need to perform a procedure known as a 'blood patch' to seal up the hole. It involves taking a small sample of your own blood and injecting it into the epidural space. When the blood clots, the hole will be sealed and your headache will stop. Post-dural headaches are uncommon following an epidural. There is a 1 in 100 to 1 in 500 chance of it happening. Please note, for women that have had an epidural, not all headaches, during and after labour are because of a post-dural puncture. There are many other causes including tension headache, migraines and preeclampsia.
  • Click here for further information on post-dural headache.

Very Rare

  • An epidural abscess is an infection (a collection of pus) that forms in the tissue that surrounds the spinal cord. The abscess may surround the spinal cord and cause enough pressure to affect neurological function. The treatment for an epidural abscess is surgical drainage and intravenous antibiotics
  • An epidural haematoma is a collection of blood within the epidural space, which can result in spinal cord compression. Treatment will generally require surgical decompression.
  • 'Pins and needles', numbness or weakness can sometimes persist after epidural or spinal anaesthesia. In approximately 1 patient in 10,000 this may be long lasting or even permanent.

Additional Reading