Association between severity of pain, perceived stress and vagally-mediated heart rate variability in women with endometriosis.

Chronic pelvic pain is the main symptom in women with endometriosis. Evidence suggests that psychological stress and autonomic regulation contribute to symptoms and pathophysiological modulation. We investigated the relationship between endometriosis-related pain severity, perceived stress, and autonomic balance in a sample of 81 women suffering chronic pelvic pain with deep endometriosis. Perceived stress and pelvic pain symptoms were assessed using the 10-item version of the Perceived Stress Scale (PSS-10) and the Numeric Pain Rating Scale (NPRS), respectively. Autonomic nervous system regulation was evaluated using vagally mediated components of the heart rate variability (vmHRV). Our results showed that pain unpleasantness and perceived stress were positively correlated, and women with mood disorders had higher perceived stress. The women with low resting vmHRV experience more intense pelvic pain, pain unpleasantness, and a higher number of severe endometriosis-related pain descriptors. The positive association between perceived stress, mood disorder, and pain unpleasantness demonstrates the additive effect between these aversive experiences. The inverse association between parasympathetic tone and pain suggests contributions of the Descending Inhibitory Pain pathway efficiency to symptom severity in women with endometriosis.