Epidural: The Pros and Cons

How does an epidural work?

The anaesthesiologist inserts a needle between two vertebrae in the lower back, stopping just short of the sac enclosing the thick cable of nerves (spinal canal) inside the spine. A fine catheter is threaded through the needle, which is then removed. Next, a mixture of local freezing agent and morphine-like medication is piped in through the tube, causing numbness below the waist.

The pros of an epidural

In most cases, an epidural provides very effective pain relief. And if you are having a difficult labour, this could make the difference between a positive birth experience and a negative one. An epidural can also be very useful in the following situations:

• Sunny-side-up baby: If your baby will not move, facing your belly button instead of your backbone, an epidural may relax the muscles of the vagina and perineum, giving the baby just enough wiggle room to rotate and descend.

• Exhaustion: If contractions have kept you awake for a long time, a nap made possible by pain relief can give you a second wind.

• Hypertension: During labour high blood pressure, which can soar further during pushing, poses dangers including a small risk of stroke. One of the side effects of an epidural – a decrease in blood pressure – can reduce these risks.

• Need for forceps or vacuum: An epidural prevents discomfort.

• Non-emergency caesarean section: An epidural allows you to remain awake during the birth. General anaesthesia is only needed in very urgent situations, which account for a small minority of C-sections.

The cons of an epidural

Did you know that epidurals do not always work? Roughly five to ten per cent of the time, an epidural only provides patchy, partial relief, for instance numbing only one side of the lower body. Adding more medication or redoing the epidural corrects the problem in about 75 per cent of those cases. If you are one of those – albeit few – cases where the epidural does not work as expected, this can be extremely disappointing.

• Limited mobility: Most epidurals keep you more or less immobile. But even if the resulting numbing is light enough to allow you to move your legs (a type of epidural that is only available in a handful of hospitals), in most centres you will automatically be hooked up to an IV and a foetal monitor, so you will not be able to walk or move around.

• Less effective labour and pushing ability: This side effect can not only lengthen labour, but can also substantially increase the likelihood of a forceps or vacuum delivery. Some doctors say the likelihood increases by around 38 per cent, while others estimate that epidurals double or even triple the odds. Furthermore, over half of women who have an epidural will need the hormone oxytocin (which has its own risks) to strengthen slowed or stalled contractions.

• Drop in the mum’s blood pressure: This can cause the baby’s heart rate to slow down, which is sometimes a sign of distress. If IV fluids and drugs do not bring the mum’s blood pressure and the baby’s heart rate back to normal, a C-section is usually the next step.

• Perineal injury: Tears and other injuries are more common because epidurals increase the risk of a vacuum or forceps delivery.

• Fever: For reasons that are not completely understood, an epidural significantly increases the likelihood of developing a fever during labour. In one study from the year 2000, nearly 12 per cent of women who received an epidural ran a temperature of 37.8°C or higher compared with only 0.2 per cent of those who did not receive an epidural. In case the fever signals infection, typically mother and baby are both treated (often unnecessarily) with antibiotics. The baby may also be admitted to the NICU for close observation.

Considering the pros and cons of epidural anaesthesia, you should make your own decision before the onset of labour so that you have at least one less decision to make and can concentrate on the labour and birth. Talk to your healthcare provider or midwife for advice.