A guide to TENS

How does it work?

A small battery-operated stimulator transmits gentle, electrical impulses through your skin, via four self-adhesive pads positioned on your back. These gentle impulses stimulate your body to release its own natural painkiller, endorphins, and by stimulating the nerves, pain signals are blocked before they reach the brain (often referred toas the 'gate theory').

The intensity of the impulses can be altered as labour progresses. Electrodes are attached to the pads, and there's a hand-held control box, which is usually small and unobtrusive.

What does the evidence say?

As a form of pain relief, the concept has been around a long time, it was first recorded by a Roman physician about 2,000 years ago. Research shows that TENS machines are most effective when they're introduced in early labour. A distinct advantage of using a TENS machine is it means women are able to stay mobile during labour. This helps the baby's head to move lower, and encourages contractions, which therefore postpones or avoids the use of epidurals.

When should I use it?

If you hire a TENS machine, it's best to get it around the 37th week of pregnancy. Play about with it, work out where to put the pads and how to operate the controls. It's important that you're familiar with it before labour.

What are the advantages?

A TENS machine offers the chance of drug-free pain relief, allowing you to stay alert and keep mobile. It's completely natural, doesn't affect your baby in any way and is easy to self-administer. It can be used with other forms of pain relief, and is especially useful for post-caesarean pain relief.

What are the disadvantages?

Not all NHS facilities have TENS machines, so you might have to hire one yourself. Also, you can't use it if you have a bath or use a birthing pool. Plus, it isn't suitable for women with epilepsy or heart pacemakers.

Anne Richley, midwife.

More help and advice

- Pain relief options during labour
- Insider's guide to labour and birth
- Inducing labour
- Embarrassing pregnancy questions answered
- Caesareans explained

By Anne Richley, midwife