Relationships between pain, cognitive activity and epidural analgesia during labor.

This study examined the dynamic interplay between subjective pain, pain behavior and cognitive activity during the latent (less than or equal to 3 cm), mid-active (5-7 cm) and transition (greater than or equal to 8 cm) phases of labor in 115 nulliparous women. Subjects received no analgesia during the latent phase and either no analgesia or epidural analgesia during the active and/or transition phase. Data were analyzed according to phase and analgesic condition. For subjects with no epidural analgesia, both the Present Pain Intensity (PPI) and the Present Behavioral Intensity (PBI) scores were correlated within and between phases. In contrast, Coping/Distress scores were weakly correlated between the latent and active labor phases and were unrelated between the active and transition phases. PPI and Coping/Distress scores were highly correlated within the latent phase but were independent within the active and transition phases of labor. PBI and Coping/Distress scores were moderately correlated within the latent and active phases and were unrelated during the transition phase. Epidural techniques reduced subjective pain and pain behavior significantly but had no apparent effect on the coping or distress-related cognitive activity characteristic of active labor. We concluded that coping and distress-related cognitive activity in labor may follow a phase-specific pattern which is relatively independent of pain or pain relief after labor has become active.