Low-back pain during labor.

Earlier studies have shown that labor pain is highly variable in intensity and spatial location. Most women feel pain predominantly in the abdominal area whereas others complain about severe back pain. In addition to the pains associated with contractions, many women report continuous low-back pain. This study used the McGill Pain Questionnaire to examine each type of pain. Women during labor also tracked their perceived pain levels at the same time that contractions were registered on cardiotachographic records. The results show that continuous low-back pain is severe and is reported by about 33% of women during labor. It is described as being qualitatively different from the pains associated with uterine contractions. The pain of contractions felt in the back is often reported as "riding on" the continuous low-back pain so that both together may reach "horrible" or "excruciating" intensities. Continuous low-back pain is probably caused by the distention and pressure on adjacent visceral and neural structures in the peritoneum, in contrast to the rhythmic pains that are clearly related to contractions of the uterus. It is possible that each of these major kinds of pain may be controlled by different anesthesiologic and psychologic procedures.