Pain in Childbirth

What causes pain in labor?

Natural Result of Physical Processes. During labor and birth, there are several physical processes occurring that lead to childbirth pain: the strong uterine contractions and the tension they place on supporting ligaments; pressure of the baby on the cervix, vagina, urethra, bladder, and rectum; stretching of the cervix, pelvic floor muscles, and vagina. These processes are unavoidable, and the pain caused by them is a positive sign that labor is progressing. We don’t want to stop these processes from happening, we just have to figure out how to minimize the pain we experience as a result.

Pain-intensifying factors that we can influence.

• The stretching of the pelvic floor muscles can cause pain; it helps if you’ve been doing your Kegel exercises in advance.
• Pressure on bladder causes pain, going to the bathroom regularly during labor helps.
• Emotional and psychological issues from our past can influence our attitude toward pain, and our ability to cope with labor pain. Awareness of these issues, counseling prior to labor, and supportive companionship during labor can help with this.
• Reduced oxygen to uterine muscle increases pain; breathing techniques help.
• Muscle tension increases pain, fear and anxiety make you more sensitive to pain; relaxation can help with these.

Gate Theory of Pain

The nerve fibers which transmit labor pain sensations unmyelinated and carry nerve impulses more slowly than the nerve fibers which carry sensations of light pressure, soft touch and vibration. If you transmit pleasurable impulses (such as light, soft touch), those will reach the brain first, and that can modulate, or interfere with, the pain sensations.

• Merkel’s disks are nerve endings which transmit sensations very quickly to the brain. They are most focused in the palms, the soles of the feet, and the lips. Thus, having partners hold a mom’s hand, rub her feet, or kiss her can all help interrupt the pain sensations. Moms can also grip the rails of the bed, or stand up to activate some of these sensors.
• Meissner’s corpuscles are found in the fingertips, and sensations from them are transmitted quickly. Having the woman move her fingertips in circles on the sheet, or finger soft textures like velvet or stuffed animals, or feel her partners face, can help minimize pain transmission.
• In general, sensory input can distract us from pain perception. This can be seen from common experiences, such as going to a movie and forgetting about a headache until the movie is over; or finishing up work on a focused project and then realizing that it’s been hours since you’ve gone to the restroom. Therefore, any sensory input the mom finds pleasant and relaxing can help: massage, light touch, music, a focal point to look at, aromatherapy, etc.

Fear –Tension – Pain Triangle

During labor, fear and anxiety can worsen our pain: they cause the release of stress hormones (catecholamines: epinephrine, etc.) which place us in a hyper-aroused state that makes us hypersensitive to pain. Catecholamines increase our heart rate, increase blood pressure, slow down digestion, and shunt blood supply away from internal organs and toward skeletal muscles and skin. All of these things in excess can cause complications in labor, and prolong the labor.

Fear also leads to muscular tension, which increases our experience of pain. Using relaxation techniques can help to reduce the muscle tension.

The concept of the fear-tension-pain triangle has arisen: when fear increases, tension increases, which then increases pain. Then the increased pain increases fear, and the situation continues to worsen.

The uterus contains two opposing muscle groups – one to induce and continue labor, and another to stop labor if the birthing mother is in danger and afraid. When we are frightened, we release adrenaline, which causes the short, circular muscle fibers in the lower third of the uterus to contract, stopping labor by closing and tightening the cervix. At the same time, the long straight muscle fibers of the uterus are contracting to dilate the cervix. The two powerful muscles pulling in opposite directions during every contraction causes more severe pain. (Griffin)

Thus, anything that can be done during labor to help the mother feel calm, relaxed, and safe can help to minimize the pain that mother’s experience in labor. Some specific things you can do. Prior to labor: educate yourself about labor so there’s less fear of the unknown. Throughout labor: Think about environmental factors such as dim lights, quiet music, and nice smells. Bring to the hospital: favorite clothing or blanket, etc. Use relaxation techniques and breathing techniques.

Janelle Durham, 2002

Sources: Pregnancy, Childbirth, and the Newborn by Simkin, Whalley, and Keppler (2001 edition). “Epidural Express” by Nancy Griffin, Mothering, Spring 1997. “The Pain and Discomfort of Labor and Birth” by Nancy Lowe, JOGNN, 25: 82-92, 1996. “Nonpharmaceutical Pain Relief” by Hilbers and Gennaro, source unknown, perhaps published as conference proceedings.

Labor Support

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