What is TENS and how does it work?
TENS stands for Transcutaneous Electrical Nerve Stimulation. A small, mobile unit sends electrical signals to nerve endings in your skin to block the transmission of pain to your brain and to stimulate your body to release endorphins, it's own natural pain killers. The signals are delivered to your skin via gel-covered pads wired to the unit and attached to specific places on your back. The signals can be varied in frequency and intensity as contractions become stronger.

When can I use TENS?
Research has shown TENS to be most effective when used from the onset of labour because it takes some time for your body to start reacting to the impulses. Many women find it most effective in the first half of labour when contractions are less strong, but it can also work for some women throughout labour - particularly for a second or subsequent child. It's commonly used in combination with Entonox (gas and air). You can't use a TENS machine if you are labouring in water or if you have a pacemaker fitted.

Advantages

  • Works externally so does not affect either the baby or the mother's chemical balance
  • There is no evidence of medical risks associated with using TENS
  • Allows you to be mobile
  • Doesn't interfere with your control over labour
  • You control it completely and can stop whenever you feel it's not working for you
  • Can be used in conjunction with other pain relief, such as gas and air
  • Can be used for homebirths

Disadvantages

  • If you have to hire a TENS machine it will cost about £30
  • You may find that the TENS doesn't do much for you, or that the added stimulus becomes irritating (but in that case you can simply abandon it)
  • The machine may have to be temporarily removed if the fetal heartbeat needs monitoring
  • The placement of pads on the back can make masssage through labour more difficult
  • You can't use TENS in a birthing pool

Availability
TENS machines are becoming increasingly popular with patients and midwives and are now often available in hospitals, but it is worth checking how many are available - and how many women they are to be shared between. If there are few or no TENS machines available, or if you're having a homebirth, then you can either buy a unit or hire one for a month period. Hiring a machine also (usually!) gives you the opportunity to familiarise yourself with it before the crucial time. There are plenty of different models to choose from, so ask your midwife for some advice.

If the birthing centre or hospital provides TENS machines they may well have advance demonstrations to explain how to use the machine most effectively.