Physiologic Labor

Sources of Pain during Labor

ligamentsAt the most basic level, labor is a physiological process the mother completes to get her child out of her body and into her arms. As such, there are a wide variety of factors that contribute to the way this physiological process feels to the mother and how she perceives the sensations. To help you understand, let us think for a moment about a physiological process you are more familiar with, digestion.

The process of digestion requires several organs, a large percentage of the body and can produce a wide variety of pains. When all is working well, the discomforts you feel from an empty stomach or full bladder are gentle indications to you of your body’s needs. When all is not well you may feel pressure, muscle constriction, muscle spasm, nausea or even damage to the tissues of your mouth such as a burnt tongue.

The process of labor uses fewer body parts than digestion, but can produce just as wide a variety of pains. Like digestion, the intensity of the sensations felt by a mother can range from gentle indications something needs to be done to pressure, muscle spasm or even tissue damage in rare instances.

With digestion, the behavior of the person can affect the level of comfort. Eating known triggers can cause heartburn and decrease comfort. Eating high fiber foods can improve the functioning of the digestive system and therefore increase comfort. The laboring mother has a similar ability to affect the level of her comfort. Changing positions is commonly known to increase comfort, while lying on the back is known to decrease comfort.

While there are some factors the laboring mother can control, such as what position she is in, there are other factors affecting her discomfort she is not able to control. With digestion some women are not able to tolerate certain foods or are prone to heartburn. With labor, some women are slower to produce hormones necessary for the process and other women have narrower pelvis requiring a larger stretch. Additionally, labor comfort is affected by the position of the baby, amount of rest the mother has had, the mother’s overall health and the mother’s confidence. Because of this, different women can go through the same process of labor and experience different sensations.

Understanding all that, here are the commonly accepted theories for the physical sources of pain in childbirth, and theories about how they can be overcome (where possible). Please remember the extent to which these cause pain in labor varies from woman to woman and from labor to labor.

The Uterus

During contractions, the blood flow to the uterus is blocked. This deprives the uterine muscle (and the baby) of oxygen for a few seconds. As the contractions become longer and closer together, the blood flow is blocked for longer amounts of time and more frequently. Muscles use oxygen to operate efficiently. When oxygen is not available muscles use a different mechanism that causes a build up of lactic acid, therefore the decrease in oxygen to the uterus may be a source of pain. Allowing the uterus to relax completely between contractions will allow the highest level of blood flow to the uterus. Help the mother use relaxation exercises to help improve the oxygenation and avoid using labor stimulants such as oxytocin which give unnaturally long and frequent contractions.

The Cervix

During labor, the baby’s head puts pressure on the cervix and stretches it open. Keeping the bag of water intact as long as possible helps to equalize the pressure on the cervix, opening it evenly and avoiding high pressure areas.

Surrounding Tissues

The ligaments, nerves, muscles and joints surrounding the uterus are stretched and may be exposed to pressure during labor. Use position that minimizes pressure and use relaxation to keep muscles soft and flexible to move with contractions.

Pelvic Pressure

The pelvic floor, bladder, rectum and urethra are put under pressure during labor. Use positions that increase the size of the pelvis and decrease pressure on the pelvic floor. Keep the bladder empty to minimize pressure.

Stress Hormones

The body’s natural response to stress, anxiety and fear causes the uterine muscle to work to constrict the cervix, causing unproductive contractions and increasing pain. Prevent the release of stress hormones by being prepared for labor and using relaxation techniques to stay calm.

Jennifer (Author)