Mind-altering narcotics or leg-numbing epidurals are not the only means of true pain relief in labor. There are alternatives, and one that is rapidly growing in popularity is the nonpharmaceutical TENS unit.
TENS stands for Transcutaneous Electrical Nerve Stimulation – a big name for a small device that delivers an electrical pulse to the skin, stimulating the nerves for relief of muscle discomfort. That little pulse is a boon for birthing moms, since the uterus, back and legs are all muscles at work when a woman is in labor. TENS units are widely used in the U.S. for physical therapy and some chronic pain conditions. But, following the lead of Great Britain and other countries, more and more U.S. women are using them to manage birth discomfort.
That is due in large part to Seattle childbirth guru Penny Simkin, a physical therapist, doula and childbirth educator. Simkin first brought TENS units into local labor and delivery units in the 1980s. Interest in them was slow to rise locally, but has intensified in the last few years.
The TENS unit is used in labor by applying four sticky pads (electrodes) to specific areas on the woman’s back. Thin wires lead from the electrodes to a small hand-held device that the mother controls. With a push of a button, she dictates the intensity of the electrical pulse she feels. The current passing through the electrodes stimulates the release of endorphins, the body’s natural pain reliever.
When a contraction begins, the woman can dial the intensity up, and as it subsides she can dial it down. She can also alternate between a steady current, a pulsing current, or turn the unit off entirely. The sensation is often described as tingly, like the pins and needles feeling you get when your foot falls asleep.
The light pulse delivered by the TENS unit does not go into the muscle – or to the fetus. It is subcutaneous (under the skin) stimulation, and therefore completely safe for the baby.
Warning! Not all TENS units are alike. TENS units used in labor have a specific frequency and current. Their low intensities stimulate the large diameter nerves that inhibit activity in the smaller nerve fibers, therefore closing the “gate” to the brain and lessening the perception of pain. This is known as the Gate Control Theory of pain relief. Labor TENS units are also very small compared to other TENS units, and have one or two simple dials so the laboring woman isn’t dealing with complex controls in the middle of contractions.
Most women in the U.S. who use a TENS unit get it from a birth doula. It is important that doulas or parents who use a unit have adequate training. TENS training for use in birth is currently available through DONA International.
Doulas in the Seattle area report that the TENS has become one of the most-used tools in their birth bags. The unit can be used for any kind of labor pain, whether it is in the belly, back or legs. But it is most effective for pain experienced in the back, which may be a sign of a baby who is not in the optimal position. No matter where mom feels discomfort, the electrodes are applied only to the woman’s back, never to her abdomen.
“Nine of out 10 of my clients opt to use the TENS,” says Cheryl Murfin, a longtime Seattle doula. “What I find is that even for those who are experiencing intense contraction pain in the lower pelvis, and very little in the back, the unit provides relief. Ultimately, it is very hard to concentrate fully on the sensation of the contraction when feeling the deep massaging pulse of the unit. Women tell me it’s enough distraction to allow them to cope.”
Studies done in the United Kingdom and Taiwan on the efficacy of TENS in reducing in labor pain don’t necessarily bear out what women in Seattle and around the world are reporting. They did not prove the units actually reduced pain. With that information in mind, local experts on TENS use are pondering whether the benefit of TENS isn’t so much about how much pain it takes away, but rather how much it helps a woman actively participate in mediating her own labor discomfort.
TENS should not be used by those with pacemakers or seizure disorders. It should not be worn in water. And it should not be used before 37 weeks of pregnancy. Using TENS does not impact a woman’s thinking. Other than water, there are no restrictions of movement while the unit is on. You don’t need a license to operate it – although training is recommended.
In other countries, TENS are considered so safe that parents can buy or rent one at a local pharmacy without a prescription. In the U.S., obstetrical TENS have not been approval by the FDA, so they cannot be sold in pharmacies. Interested parents should ask their doula or midwife if they have access to a unit. Or, go online to purchase a unit from the United Kingdom.
“Frankly, I find that I have a hard time getting my TENS unit off the moms I work with,” says Murfin. “If it works, they really cling to it, and I know it has saved many a woman from an epidural – even one they planned on getting. One mom refused to take it off even after the baby arrived – the massage sensation just felt good to her!”