Epidurals in Labor

  • April 27, 2017

Epidurals in Labour


 What do you know about epidurals and their risk and benefits?  

Epidurals are a very effective method of pain relief for labouring women, and are often encouraged by caregivers, even before labour begins.

Like all interventions, epidurals have benefits and risks for mothers and babies. Possible risks include the potential to disrupt the processes of labour for mother and baby. There are also unanswered questions about possible impacts through to motherhood, including effects on breastfeeding and bonding.

These FAQs will help you to balance the benefits and risks of epidurals  for yourself and your own unique situation, so that you can make the choices that are right for you, your baby and your family.

What is an epidural?

Epidural analgesia involves an injection into the lower back that pierces the outer coverings (”epi-dura”) of the spinal cord. Drugs are injected close to the nerves as they come out from the spinal cord. Usually this involves a “local anaesthetic” (LA) drug such as bupivacaine, along with an “opiate” drug (related to morphine, pethidine/meperidine etc) such as Fentanyl. Epidurals are used in many types of surgery and procedures, and also sometimes administered to receive pain outside  of childbirth.

How do epidurals work?

Just like a dental anaesthetic, LA drugs block the sensory nerves, causing numbness, and also inevitably block the motor nerves, giving some degree of paralysis. Opiate drugs are added to an epidural to increase the effectiveness of the LA, so that there will be good pain relief with less motor block.

What are the benefits of epidurals?

Obviously, the main benefit of an epidural is the very effective pain relief that most women experience. Because of this effective analgesia, epidurals also reduce stress, and stress hormones, in labour. This can be beneficial when women are experiencing very high levels of stress and pain, which can slow labour progress.

Is labour stress harmful?

It is important to realise that some degree of stress is inevitable in labour, and actually beneficial for mother and baby. For example, high levels of the stress hormone cortisol contribute to a new mother’s euphoria, and help with bonding with her newborn. For the baby, the “stress of being born” switches on biologic processes that help with breathing at birth, among other adaptations. (See below for references)

Are epidurals good if I need a caesarean?

Epidurals also allow you to be awake and alert, but pain free, when procedures such as caesareans are needed. You will be able to see and hold your baby soon afterwards. In this situation, you and your baby will also be exposed to lower levels of drugs than a “general anaesthetic.”

What are the side-effects of epidurals?

Many of the side-effects of epidurals are due to effects on your  birthing hormones. These are the calming, pain relieving, and stress-reducing chemicals that your body naturally produces to make labour as easy, safe and rewarding as possible.

How do hormones help in labour?

The hormone oxytocin is particularly important because it causes the uterine contractions that drive labour and birth.

During a natural (physiologic) labour and birth, the sensations of uterine contractions are transmitted to the labouring woman’s brain, and start the oxytocin “positive feedback cycle” (Ferguson reflex). Within this cycle, uterine sensations trigger oxytocin release, more contractions, more sensations, and more oxytocin release. This strengthens labour and also helps the baby to be born quickly and easily.

As the diagram shows, this positive feedback cycle also increases oxytocin release into the brain, where it has calming and pain relieving effects. (Very welcome in labour!)  Oxytocin also turns on reward and pleasure centres in the brain during labour and birth, in preparation for mothering.

Why do epidurals slow labour?

With an epidural, your labour sensations will usually be completely abolished. This means that there is no sensation to drive this oxytocin feedback cycle, and your oxytocin levels will decline.

This explains why labour usually slows, and sometimes even stops, in the hours following epidural administration. You will probably require an infusion of synthetic oxytocin (Pitocin, Syntocinon) to compensate for the loss of your own oxytocin, and to strengthen labour again.