Health Tip: TENS machine and Pregnancy

What is TENS?

Using a TENS machine is a common form of  labour pain relief in the UK. It is not as popular in Canada yet. If you are looking for non-medical pain relief, a TENS machine may be just the thing for you.

TENS stands for transcutaneous electrical nerve stimulation. A TENS machine consists of a small box, with a clip on the back that you can attach to your clothing. The machine gives out little pulses of electrical energy.

Leading out of the box are four wires connected to sticky pads. Your birth partner can place the pads on your back for you. Follow the instructions that come with your TENS machine. Two of the pads are placed on either side of your spine at about bra-strap level. The other two go lower down, at about the level of the dimples in your bottom. The pads are covered in a gel to help the electrical pulses pass through your skin more easily.

The TENS machine has dials that you can adjust to control the frequency and strength of the pulses. There's also a boost button for you to hold in your hand and press when you want maximum output from the machine to help you with a difficult contraction.


How does a TENS machine work?

We don’t know exactly how TENS works, although there are a number of theories (Dowswell et al 2008). One is that the electrical pulses prevent pain signals from reaching your brain, while another is that the pulses stimulate your body to release its own, natural, feel-good substances, called endorphins (Millns and Eagland n.d.).

It's also likely that various factors interact to make TENS work. TENS may help you to feel that you have control over your contractions, it may help you to feel less anxious, and it also may provide a distraction from your contractions (Dowswell et al 2008).


When and how should I use TENS?

TENS seems to work best and give you the most effective pain relief if you start using it at the very beginning of your labour (Blincoe 2007:519; MIDIRS 2008:14), so rent a TENS machine and use it at home before you go into hospital, if you're having a hospital birth.

It takes about an hour for your body to respond to the electrical impulses by releasing endorphins, so start using it when you're getting regular contractions or backache. You may find your machine works better at relieving your backache than abdominal pain (Simkin and Bolding 2004).

Start with the controls at their lowest settings and turn them up gradually as your contractions or the back pain gets stronger. Use the boost button at the peak of contractions.

You will need to call a physiotherapy office to track a TENS machine down. If you have a hospital that specializes in woman's care near you, try the physiotherapy department there. Or if you are lucky enough to have an obstetrical physiotherapist in your town, try calling her office. Your doctor or midwife can help you track one down; ask for her help during a prenatal appointment.


What are the advantages of TENS?

  • It's portable and non-invasive.
  • It's under your control.
  • It's easy to use.
  • You can keep moving while using it.
  • You can use it for as long as you want and then take it off. There are no lasting side-effects.
  • It's safe for your baby (MIDIRS 2008:14; Millns and Eagland n.d.).
  • It doesn't need an anaesthetist, doctor or midwife to administer, so you can start using it as soon as you want to.
  • It can be used for a home birth.


What are the disadvantages?

  • You will need someone to help you put the pads on.
  • It may only help in the early stages of labour (Blincoe 2007:519; MIDIRS 2008:14).
  • It may be difficult to find a TENS machine in your area.
  • It may have to be removed if your baby's heart has to be monitored electronically (MIDIRS 2008:14).
  • If you want to use a birthing pool or have a bath, you can use TENS before you get in the water, but not when you are in the water.
  • It can makes it more difficult for your birth partner to massage your back, which can be an effective form of pain relief.


Any useful tips?

  • Don't give up straight away if you think your TENS isn't doing anything. You need to keep using it for at least an hour to give your body time to build up endorphins in response to the stimulation (Blincoe 2007).
  • Take the pads off every three hours and smear them again with gel before reapplying them. This ensures that the contact with your back is really good.
  • Keep mobile. Moving around during labour helps women feel more in control and should therefore enhance the effect of TENS.
  • If you don't think it's helping you, take it off and don't feel bad. You've lost nothing (except your rental fee). Allother forms of pain relief, both medical and non-medical, are still open to you.

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