A rise in pain threshold during labor: A prospective clinical trial

Abstract

To evaluate changes in pain threshold before, during and after labor in a prospective clinical trial. Forty pregnant women at term were included. Pain threshold in 18 specific pressure points was evaluated using a dolorimeter. Woman underwent pain threshold assessment at term before labor, during the active phase of labor and postpartum. Subjective pain intensity was assessed by the parturient using the Verbal Rating Scale (VRS). Pain threshold was significantly higher during active phase of labor. There was a significant decline in pain threshold after labor as compared to pain threshold during labor (2.507+/-0.947 and 2.608+/-1.023, respectively, p=0.01). Pain intensity using the VRS score was higher during labor than before labor (4.8+/-2.7 and 2.4+/-2.6 p<0.001). We found a significant rise in pain threshold during labor in term pregnancies. This rise may have an intended protective effect during the intense labor pain experience.

Labor pain in women with and without severe fear of childbirth: A population‐based, longitudinal study

“…37 Of the 1649 women, 119 (7.2%) scored ≥85 on the W-DEQ, indicating severe fear of childbirth. The women's reported pain perception ranged from no pain at all (0) to the most intense pain imaginable (10). Mean labor pain perception for all women was 8.17 (SD = 1.84), and most of the women (74.2%) scored above or equal to 8 on the pain perception scale (see Figure 1, first panel).…”

“…This underlines the involvement of several physiological and psychological mechanisms in the association between fear of childbirth and the perception of labor pain. [9][10][11][12]…”

“…9 Thus, it comprises at least two components-the sensory and the affective-as there is a complex interplay between endogenous nociceptive receptor-induced pain (eg, as a result of the process of birth) and the interpretation and expression of this pain stimulus. 10,12 Chemical and hormonal reactions taking place before, during, and after labor might influence pain thresholds. 10,13 Anxiety and fear increase catecholamine concentration in the plasma, which is associated with enervated uterine contractility.…”

“…10,12 Chemical and hormonal reactions taking place before, during, and after labor might influence pain thresholds. 10,13 Anxiety and fear increase catecholamine concentration in the plasma, which is associated with enervated uterine contractility. Hence, in women with severe fear of childbirth, this mechanism may augment nociceptive stimuli and magnify the perception of labor pain.…”

The correlation of antepartum upper extremity cuff algometry with epidural analgesic requirements for labor

“…Pressure pain tolerance in pregnancy has been shown to increase during labor, and remain elevated until after birth. [2] Term pregnant women are more likely to have an increased tolerance to heat induced pain as compared to controls. [3] However, little is known about how individual pain tolerances affect labor analgesia.…”