A TENS (transcutaneous electrical nerve stimulation) machine is a drug free method of relieving discomfort. It is a handheld device, connected by wires to electrodes that stick to the skin on your back. There are four pads that you place on your lower back and these send mild electrical pulses through the skin.
So how does sending electrical pulses into you back help in labour exactly? Every time you feel a sensation in your body there are signals that are sent via your spine to your brain. So when you experience a contraction in labour a your brain receives the message that uterus muscle is working hard which might be perceived as discomfort. A tens machine stimulates the nerve endings that are closest to where the message is sent from which can confuse the signal and reduce the pain signals going to the brain, which may help relieve pain and relax muscles. This is really similar to when you rub your elbow when you bang it on a door frame. This is called ‘gate control of pain theory’ the theory is that only a certain amount of sensations can get through to the brain. So if you think that there is a ‘gate’ that only lets so much sensory information through and with a TENS you are overriding the signal sent when you have a contraction.
If you use a TENS machine on a higher intensity setting it can help your body to create the pain relieving hormone endorphins. When you body detects discomfort it naturally creates this hormone, which in high levels are stronger than the drug morphine. So any discomfort created by the TENS machine, increases the body’s own pain relieving hormones, which can contribute to making labour more comfortable.
A big benefit of using a TENS is that it can be used when you are moving and in any birth position. You are in control of it and you can change the settings and can boost the electrical pulses at any time and turn it off completely. A TENS can be used with other forms of pain relief and you can remove it to get into water such as a bath or birth pool.
Here are some tips I have shared before in classes if someone was considering using a TENS machine:
⭐ Place two of the pads on either side of your spine, with the tops of the pads around bra strap level and put the other two lower down, at about the level of the dimples on your lower back, just above your bottom.
⭐ Try to use it early on in your labour to allow enough time for your endorphin level to increase and start on the lowest setting
⭐ If it doesn’t seem to work for you straight away, then give it at least an hour or so you can decide whether it is working for you or not.
⭐ Keep moving. Staying upright and mobile during labour helps you to feel in control and encourages the flow of oxytocin, endorphins and will increase the effectiveness of the TENS machine.
What does the evidence tell us? There isn’t a lot of good quality research on the usage of TENS machines, however some recent studies including a randomized controlled trials that using TENS during labour does help decrease pain and may increase maternal satisfaction as well as delay the use of pharmacological pain relief. The majority of people who have used a TENS during a previous birth would use one again.