Epidural vs spinal anaesthesia: how they differ in labour and surgery

Epidurals and spinals are close relatives. Each involves an anaesthetist injecting local anaesthetic through the lower back, so that you are awake but numb from the waist down. The difference is where the medicine goes and whether a tube stays in place afterwards.

In an epidural, a needle is used to place a fine plastic tube (an epidural catheter) in the space near the nerves, and then the needle is removed. Medicines are given through the catheter and can be topped up. In a spinal, a fine needle is used to inject the anaesthetic into the fluid that surrounds the nerves, giving a quick, dense block that wears off without a catheter. A combined spinal-epidural does both: the spinal gives rapid numbness and the epidural allows more to be given if needed.

The NHS explains that epidurals are given by an anaesthetist, usually with you awake, sitting forwards or lying on your side. The skin is numbed with a local anaesthetic, a needle places the catheter near the nerves that carry pain messages to the brain, and the needle is removed. You may feel mild discomfort during placement. The medicines take about 20 to 30 minutes to take full effect, and your chest, tummy and legs may feel numb while it is in use, with the legs perhaps less strong than usual.

The catheter can be used to top up the medicine by hand or by pump, for several hours in childbirth or for a few days after major surgery. Some hospitals offer a mobile epidural that uses a lower dose so you may be able to walk around in labour. The NHS says you will not be able to drive for 24 hours afterwards.

Labour Pains describes a spinal as the most common type of anaesthetic used for a caesarean birth. It involves an injection of local anaesthetic into the lower back to numb the lower half of the body, with a fine needle used to inject into the fluid within the sac in which the nerves sit. It works quickly and you stay awake, but should not feel pain from the waist down.

For caesarean birth, a drip is placed, monitors are attached, and you are asked to sit up or lie on your side and curl over your bump. The procedure usually takes only a few minutes. The skin feels warm first, then pins and needles, then numb, and the legs feel heavier. A catheter is placed in the bladder, and it stays until the heaviness in your legs wears off. Most people feel pressure and pulling during the operation but not pain.

The NHS says epidurals are usually safe but there is a small risk of side effects including low blood pressure, temporary loss of bladder control, itchy skin, feeling sick, headaches and nerve damage. Labour Pains describes post-dural puncture headache for both epidurals and spinals, which can occur between one day and one week afterwards and may be mild and settle in a few days or be severe and need treatment in hospital.

Labour Pains also says that, according to the latest evidence, epidurals in childbirth do not make a caesarean birth or the use of ventouse or forceps more likely, do not make a baby drowsy or cause long-term harm, and do not cause back pain after childbirth. For spinals in caesarean birth, it says they do not cause back pain after childbirth or make the baby drowsy or cause long-term harm. It adds that spinals and epidurals are usually safer for you and your baby than a general anaesthetic for a caesarean birth.

Not everyone can have one: Labour Pains lists spina bifida, some back operations and problems with blood clotting as conditions that may make an epidural unsuitable, and advises speaking to a midwife early in pregnancy if you think this applies.

The anaesthetist decides with you which is best for the situation. In labour, an epidural gives the most effective pain relief and can be topped up if you need an assisted birth or caesarean. For a planned or emergency caesarean, a spinal is the usual choice because it works quickly. If you already have an epidural working in labour and need an operation, the anaesthetist may top it up with a stronger dose instead of giving a spinal.

If you are unsure, ask the anaesthetist why one is being recommended, how long it will last, and what the plan is if it does not work well. These are reasonable questions at any stage.