gate theory

Several studies have indicated the beneficial effects of massage on the aches and pains that typically accompany pregnancy.

From tired legs to sore backs, tension headaches to stiff necks, touch therapy can reduce pain during pregnancy. But did you ever wonder exactly how massage works to relieve your clients’ twinges and pains? One theory dates back more than half a century and could still hold true today.


The Gate Theory of Chronic Pain

In the early 1960s, two professors, Ronald Melzack, Ph.D., of McGill University in Montreal, Quebec, Canada, and Patrick David Wall, D.M., of the Massachusetts Institute of Technology in Cambridge, Massachusetts, developed their gate control theory of chronic pain, which envisions a pain conduction model involving the central and peripheral nervous systems.

Their theory was published in “Pain mechanisms: a new theory,” in the journal Science in 1965. Their theory suggests that each of these systems processes pain in its own way; these nerves in the spinal column open or close depending on instructions sent by the brain.

According to the theory, fibers, or mechanoreceptors, transmit messages regarding movement, heat and pressure to the brain; nerve cells, or nociceptors, carry pain signals and lag behind the mechanoreceptors in reaching the brain.

If the first signals from the mechanoreceptors are normal, any pain messages that follow from the nociceptors will not register in the brain. Melzack and Wall further explained that if the initial signals indicate the presence of pain, the gate will be open, allowing the body to experience that pain; in the absence of pain, the gate is closed.


Gate Theory and Pregnancy Massage

How might the gate control theory of chronic pain tie into prenatal massage? Touch Research Institute founder Tiffany Field, Ph.D., examined the underlying mechanisms for massage therapy effects directly related to pregnancy and labor in a 2010 study, “Pregnancy and labor massage,” published in the March 2010 issue of Expert Review of Obstetrics & Gynecology. She wrote that the gate theory serves as a metaphor for “the pain message traveling more slowly than the pressure message from massage, i.e., the stimulation of pressure receptors.”

Field also noted that pain is transmitted more slowly by smaller unmyelinated, or less insulated, fibers and massage signals are carried more quickly by larger myelinated fibers.

For example, say your pregnant client is experiencing back pain from the weight of her growing fetus. Irritation and inflammation of the nerve endings in the muscles and ligaments, disks, vertebrae and facet joints in the back create a pain message that travels through the spinal cord and up to the brain through the peripheral nerves. Massage could help override these signals, effectively closing the gate and reducing pain during pregnancy.


Gate Theory and Labor

Not only could the gate theory apply to prenatal massage, it might also factor into labor and childbirth. During active labor, stimulation in the form of moderate pressure massage can activate “fast fibers,” release endorphins and block the transmission and perception of pain to the brain.