Labor Contraction or Braxton-Hicks?

What is a labor contraction? It is, most simply, the tightening and releasing of a muscle. When giving birth, the muscle in question is the uterus. So a contraction can be described as a tightening and releasing of the uterus for the purpose of opening (dilation) and effacing (thinning out) the cervix to allow the baby to descend from the birth canal into the mother's waiting arms.

The uterus is composed of two layers of muscle fiber, one running horizontally and the other vertically. It's the job of the vertical fibers to pull up on the uterus while the horizontal fibers push the baby down further into the birth canal.

When the vertical uterine fibers pull up and the horizontal fibers push down, the cervix is supposed to dilate and efface so that the baby descends effortlessly. But as the contraction begins, if the mother tenses assuming it will be painful, her cervix tenses.  So as the horizontal uterine fibers are pushing down, they don't meet a relaxed cervix. Rather, the baby's head is forcefully pushed against the cervix, causing pain. If instead the mother remains relaxed throughout the contraction, the uterus is able to work as it was designed, pushing the baby down against a soft cervix gradually, reducing or eliminating any discomfort in the process.

The body knows how to have a baby with no conscious effort. This is demonstrated in that pregnant women in comas have successfully given birth. The labor contraction by itself will be enough to expel the baby. No "purple pushing" required.

But, is a labor contraction necessarily a sign of labor? No, they are not. Many women feel contractions as early as the first trimester or daily throughout the latter stages of pregnancy. These contractions are termed Braxton-Hicks. They are the same as a true labor contraction in that the muscle at work is the uterus tightening and relaxing just as it will during labor. However, there are some other differences to distinguish them from the true beginning of labor:

Frequency

Time contractions from the beginning of one to the beginning of the next. True labor develops into a regular rhythmic pattern; if it is irregular, then it's most likely Braxton-Hicks contractions.

Contraction Length and Variability

Look for a pattern. True labor contractions usually last short increments (15-30 seconds) and progressively increase in duration (up to 60-90 seconds). If they're erratic, then rest and relax or go for a walk to see if their frequency changes with your activity level. If it's truly labor, then they will form a regular pattern despite your activity level.

Location of Sensation

A true labor contraction tends to start in the back and radiate around to the front of the abdomen. It encompasses the entire abdomen, especially the top due to the structure of the uterus - one set of fibers pulling up and another pushing the baby out.

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Page Last Modified by Catherine Beier, MS, CBE