Exploring the role of negative expectations and emotions in primary dysmenorrhea: insights from a case-control study

BACKGROUND: Primary dysmenorrhea, characterized by painful menstruation, significantly impacts the quality of life for women worldwide. Negative expectations and associated emotions are known to trigger nocebo effects and may also influence cyclic menstrual pain. In this study, we investigated the role of pain expectations and negative anticipatory emotions as potential contributing factors to hyperalgesia in women with severe menstrual pain, compared to women with absent or mild menstrual pain. METHODS: We conducted a prospective case-control study in women with severe menstrual pain due to primary dysmenorrhea, comparing them with age-matched women with absent or mild menstrual pain. Data collection included the Depression, Anxiety, and Stress Scale (DASS-21) at baseline, as well as daily numeric rating scales (NRS) to evaluate pain expectations, anticipatory negative emotions, and daily stress during the 10 days preceding menstruation. Saliva samples were collected to evaluate the Cortisol Awakening Response (CAR) before menstruation, and pain was assessed during the first 3 days of menstruation. RESULTS: Women with high menstrual pain reported significantly higher DASS-21 anxiety levels compared to low-pain controls, although still within the normal range (median IQR, 3 2; 5 vs. 1 1; 3, p <.05). In the 10 days preceding menstruation, the high-pain group expected significantly higher maximum pain levels than controls (median IQR, 8 7.3; 8.5 vs. 2.1 1; 3.3, p <.001), which aligned with their actual experiences of maximum pain during menstruation (6.5 4.8; 7.7 vs. 1.2 0.7; 2.3, p <.001). Anticipatory stress (2.1 0.9; 4.2 vs. 0.2 0; 0.9, p <.001), anticipatory anxiety (0.7 0.0; 2.3 vs. 0 0; 0, p <.001), anticipatory worry (1.3 0.4; 2.6 vs. 0.1 0; 0.3, p <.001), and anticipatory anger (0.7 0; 1.5 vs. 0 0; 0.2, p <.01) were also significantly higher in the high-pain group in the 10 days before menstruation. The CAR showed no significant differences between groups in the days before menstruation. Correlational analyses revealed multiple positive associations between expected pain levels, anticipatory negative emotions, and subsequently perceived levels of menstrual pain in both groups (all p-values < 0.05). CONCLUSIONS: This pioneering study supports the hypothesis that cognitive-emotional factors such as heightened pain anticipation and negative emotions intensify menstrual pain severity in primary dysmenorrhea, although causal conclusions cannot be drawn from this observational study. Strategies aimed at optimizing expectations could play a significant role in managing primary dysmenorrhea.