The short answer: a TENS machine is a modest helper, not a strong painkiller. NICE's intrapartum care guideline says there is very little evidence that it works in established labour, but no evidence of harm, and that your choice to use one should be supported. The NHS says it hasn't been shown to work in the active phase of labour, and is probably most useful in the early stages, when you may have lower back pain.
So if you like the idea, practise before the day, start it early in labour and keep your expectations realistic. For a first baby I'd hire rather than buy: Babycare TENS rents its units for £24.95 to £29.95 for seven weeks. If you'd rather own one, a decent budget unit costs around £32.
Does a TENS machine work in labour?
NICE (recommendation 1.6.7) doesn't tell midwives to discourage TENS. It tells them to support your choice, to explain that there's very little evidence of effectiveness in established labour but no evidence of harm, and that other pain relief can be used alongside it. The NHS adds that there are no known side effects for you or your baby.
The research is thin. A Cochrane review found little difference in pain ratings overall, yet most women who used TENS said they'd use it again, and no adverse events were reported. It also noted that TENS at home in early labour hadn't been studied. My reading: it won't do the heavy lifting, but something to focus on, that you control, can be worth a lot in the early hours.
How does TENS work?
Four sticky pads on your back are wired to a small battery-powered box that sends mild, tingling pulses through your skin. There's a pulsing setting for between contractions and a boost button you hold as each contraction builds. The NHS says it's believed to encourage your body to release its own natural painkillers, called endorphins, and to reduce the pain signals your spinal cord sends to your brain, though the Cochrane reviewers call the mechanism uncertain.
When should you start using a TENS machine?
- Before labour: the NHS suggests learning how to use it in the later months of pregnancy, and asking your midwife to show you. Babycare's Elle TENS 2 manual says you can try it out with two pads on your forearm, but not to use it before 37 weeks unless a medical professional advises it.
- In labour: Babycare says to start as early as you can, to give your body's painkilling chemicals time to build, then turn the intensity up slowly.
- If you're being induced: Babycare suggests starting about an hour beforehand.
Where do the TENS pads go?
On your back, never on your bump. Babycare's manual puts the top pair about 4cm either side of your spine, between your bra line and your waist, and the bottom pair about 4cm either side of your spine, between your waist and the top of your knickers. Follow the diagram for your own unit, and get your birth partner to place them. Switch the unit off before attaching or removing pads.
Can you use TENS with gas and air?
Yes. NICE says other pain relief can be used alongside TENS if you need it, and Babycare says you can still have gas and air or pethidine with it on. You can also take it off at any point.
It must come off before you get into a bath or birth pool: Babycare says it can't be used in the water. In hospital, your midwife may ask you to switch it off for a while, and Babycare's manual notes that some electronic monitoring equipment may not work properly while TENS is on.
Who shouldn't use a TENS machine?
Check your unit's leaflet, but the manufacturers' warnings broadly agree:
- Don't use one if you have a pacemaker or another implanted electrical device. TensCare adds heart rhythm problems and other electronic medical devices.
- Check with your midwife or GP first if you have a heart condition, epilepsy, undiagnosed pain, varicose veins, recent scarring or metal implants (Babycare's list).
- Mind the dates: Babycare says not before 37 weeks unless advised, and TensCare says not in the first three months of pregnancy.
- Never put pads on your bump, use it in water, use it while driving, or fall asleep wearing it (the leads are a strangulation risk).
This isn't medical advice: if anything here applies to you, ask at your next antenatal appointment.
Should you buy, hire or borrow a TENS machine?
NICE says the NHS doesn't provide TENS machines, though the NHS website says some hospitals have them. Ask your maternity unit, but plan to sort your own.
- Hire is the sensible default for one baby. Babycare TENS hires the Elle TENS for £24.95 and the Elle TENS 2 for £29.95 for seven weeks, posted in your 37th week with a pack of pads and a freepost return. If your baby is late, it's £10 a week to extend.
- Buy if you're planning another baby, or if a budget unit like the TensCare Perfect mamaTENS (around £32) costs barely more than a hire. Some units earn their keep afterwards: Babycare says the Elle TENS 2 suits after-birth pains, period pain and back pain (seek medical advice first after a caesarean).
- Borrow by all means, if it's a maternity unit with a boost button and its instructions. Add a fresh pack of pads: Babycare says to replace them once they stop sticking.
The TENS machines I'd pick
- To hire: the Babycare Elle TENS 2, our Gold Star. Its boost button doubles as a contraction timer. Around £80 to buy, or £29.95 to hire. The original Elle TENS is £5 cheaper to hire, without the timer (how they compare).
- To buy on a budget: the TensCare Perfect mamaTENS, our Value Star at around £32. It beats the Boots TENS Maternity Unit (around £40) on features, though the Boots is easier to grab in a hurry (compared here).
- To buy with a timer for less: the TensCare Perfect mama+, around £55 (Elle TENS 2 vs Perfect mama+).
- To splurge: the Elle TENS Plus, our Splurge Star at around £100, adds a pelvic floor mode for use from at least 12 weeks after birth. Only worth it if you're sure you'll use that (Elle TENS 2 vs Elle TENS Plus).
All six are scored side by side on the labour TENS machines page.
Talk to your midwife, and put it in your birth plan
The NHS suggests asking your midwife or doctor to explain your pain relief options, and writing your wishes in your birth plan while keeping an open mind. If you're planning on TENS, put it in, along with being happy to add other pain relief later.
When to call your maternity unit
A TENS machine is never a reason to wait. The NHS says to call your midwife or maternity unit if you think you're in labour, or your contractions are regular and every 5 minutes or more often. Call straight away, even in the middle of the night, if your waters break, you have vaginal bleeding, your baby is moving less than usual, you're under 37 weeks and think you might be in labour, any contraction lasts longer than 2 minutes, or you're having 6 or more contractions every 10 minutes.
If you can't get through, call 111. Call 999 if you think your baby is coming now and you have a strong urge to push.