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What is My Most Used Labor Tool? A TENS Unit!
- Melissa F. Haley
- Feb 17
- 5 min read
For clients who want an unmedicated labor, a TENS unit is one of the most important tools. I can't carry a whole birthing tub in my backpack, but I can carry a TENS!
A TENS unit is a transcutaneous electrical nerve stimulator, a machine often used in physical therapy because it helps to loosen and repair muscle. It is a handheld, battery operated device that allows complete mobility during use. TENS units deliver a small electrical pulse through gel pads that are applied to the skin. They are available over the counter and are usually about $30, although the ones made for labor are much more expensive ($100+). In birth, it is valuable for three reasons:
It works to distract the birthing person from the sensations of labor and gives them something else to focus on. This is the Gate Control Theory of pain: the body can only process so much information at once, so flooding it with a different sensation fills the "gate" of sensation with something other than pain. Usually, I encourage people to turn the TENS up during a contraction and down when it is over. Clients say that they liked having something to do and how the machine helped them establish a rhythm.
After about 30 minutes of use, the TENS unit will encourage your body to make endorphins, the body's natural pain reliever.
Use of a TENS gives a birthing person some control over their labor and may help to lower anxiety.
TENS units have been widely available since the 1960s and are very common in the UK, Canada, and Australia where you can rent one for your labor and keep it at home. Fun fact: ancient Egyptians used electrical fish for pain relief 2000 years ago! Use of electricity for pain relief is not new.
To hear a midwife explain how to use a TENS unit, check out this video. She explains the model that I carry in my bag, which clients are welcome to borrow from me based on availability. The Babycare TENS is designed specifically for labor with an easy button you can push during contractions that allows you more control over the different sensations.
TENS units are not as well researched as they could be, but there is some compelling evidence to suggest usage.
TENS use lowers pain intensity (Shahoei, 2017; Johnson, 2022; Rashtchi, 2022)
TENS use shortened the length of labor (Kaplan, 1998)
People who used a TENS said they would use it again (Kaplan, 1998)
Use of TENS lowers the self-reported severity of back pain (Bundsen, 1982)
TENS use lowers the rate of epidural (Kaplan, 1998)
Those who used a TENS waited 7 hours before requesting an epidural, versus just those in the control who waited an average of only 2 hours (Santana, 2016)
To learn more about the research, you can watch this video.
Frequently Asked Questions
What does it feel like?
Many people describe the feeling as "pins and needles" like when your foot falls asleep and is waking back up. Others say it is like a buzzing. I use one regularly for painful periods. I find that when I first put it on it can feel slightly uncomfortable or surprising, but after a minute or two it begins to feel good.
How long can I use the TENS?
There is no maximum amount of time you can use the TENS. You can put it on in early labor and peel it off your sweating body while holding your newborn. I find many people use it in early labor and into active labor. Often my clients rotate from TENS to shower or tub and then back again.
Does the TENS hurt the baby?
No study has ever found any adverse affects for baby during or after labor. There is no evidence of any harmful effects in labor.
Anecdotally, when my clients put the pads on they often experience a lot of baby movement. We think it is because the baby can hear the buzzing.
Can I wear a TENS unit while also wearing the hospital baby monitors?
You will need to talk to your care provider. Some have heard of a TENS. I've had L&D nurses squeal in glee at seeing one. Others haven't heard of it and are suspicious. There is no know interference of the baby's heart monitors.
Midwives are usually very happy for you two use a TENS, but you can still talk it over with them.
Where do you place the pads?
I recommend using the larger pads (rather than the smaller square ones) to get the best coverage. You place one pair near the underwear line and another pair just above it, where a bra line would be.
Will the TENS interfere with my ability to listen to my body's natural signals?
During labor, your body is going to make endorphins on its own. These natural pain killers will help you cope with labor sensations. These hormones are what make people feel like they are in "laborland" or have that natural birthing high. The TENS unit is going to help you make more of these same chemicals. One of the benefits of the TENS is that it gives you some pain relief without affecting your mobility or your mental clarity because it is not a medicine.
Is there a situation where the TENS is not advised?
There are 4 scenarios where a TENS unit is not advised: for people with a seizure disorder, for people with a pacemaker, for anyone who is experiencing a rash or wound in the area the electrodes would be placed, and for anyone preterm (36 weeks and earlier).
If at some point during labor you choose to get an epidural, we discontinue the use of a TENS. We don't want to use anything on an area of your body where there is no sensation. Another example is not putting a heat back on a spot on your body that is numb: you can't get feedback from your body that it is too much if you can't feel that area of your body.
Also, the TENS uses electricity, so it cannot be used in water.
Are there any disadvantages of using a TENS in labor?
Some people find that the sensation of the TENS is too little or too much. Others find that they just don't like the sensation or find it distracting. The most common complaint I hear is from people who wait to put it on and then find that it is not effective is later, more active labor. In order for the TENS to be most effective, you will need to begin using it in early labor.
TENS units are a helpful tool for early labor, whether you are planning to use medication or not. I highly recommend that you get one and try it out on your arm so that you know how it works. After week 37, you can put it on and test it on your back. If you suspect you're in early labor, it is never too early to try it on and see if its helpful. The pads are reusable so you can always just take it off and try again another time.
I always recommend to clients that they give it a full hour of use before deciding if they like it or not, because there is a study that showed no difference in pain ratings at 1 hour, but a significant difference at hours 2, 3, and 4 (Shahoei, 2017). My usual advice is when labor starts, especially if it begins in the middle of the night, take a relaxing shower and drink a large glass of electrolytes. Then, get into bed with a TENS unit on your back and a rice sock on your front. Try to get some sleep.
If you would like to talk more about TENS use, or find out if I have a TENS unit available for you to borrow in labor, please reach out to me. This is truly one of my favorite tools and one I feel so proud to be able to offer to my clients.
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