Epidural pain relief in labor

Epidural analgesia is a method of pain relief that involves the injection of a local anesthetic in the lower spine. This acts on the nerve roots that control pain sensation in the lower abdomen, the pelvis and the lower limbs. The effect is freedom from labor pains. A fine flexible catheter is left in place to allow repeated top-ups of the local anesthetic as and when the effect starts to wear off.

Alternatively, the anesthetic may be infused continuously rather than intermittently through this fine catheter.

The epidural is far and away the most effective method of pain control available for a laboring woman. In fact, the epidural is the only method which can render the laboring woman completely pain-free. No other method currently available can achieve this.

Reliability of the epidural in labor

Epidural analgesia works in the majority of cases. Unfortunately, for a small minority of individuals, the epidural may not work very well and they will continue to feel pain. The most likely failure of an epidural is a scenario where only an isolated area remains unaffected. This is commonly called a "window". Because the rest of the region is completely pain-free, the pain in the window area is felt quite acutely. It is often difficult to solve this problem, short of replacing the catheter.

It needs to be emphasized that epidural failure is an uncommon event.

Other epidural advantages

The pain control from an epidural is so effective that if, for some reason, a cesarean section becomes necessary, the epidural will usually be adequate for the procedure. Only a top-up is usually required. This is, of course, if the laboring mother is not averse to the idea of staying awake for the operation.

Needless to say, a working epidural is more than sufficient for forceps or ventouse delivery.

Administering the epidural

To insert the epidural catheter requires expertise and this is done by an anaesthetist. Trained midwives will give top-ups or monitor the infusion.

Unwanted effects from the epidural

Occasionally, there are unwanted effects, all of which can be solved easily. An immediate unwanted effect could be an ‘ascending epidural’, where the effects extend upwards to affect the chest and the respiratory muscles.

An ascending epidural will produce respiratory difficulties, which will require a change in position to a semi-sitting or propped up posture and, occasionally, respiratory support. It soon resolves. Fortunately, this is an exceptionally rare occurrence.

The epidural also tends to lower the blood pressure and that is why an intravenous infusion will always be started before the epidural, to offset this effect.

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