Are there any cross-ethnic differences in menstrual profiles? A pilot comparative study on Australian and Chinese women with primary dysmenorrhea

Aim: To explore and compare the features of menstruation, perception and management of menstrual pain between two cohorts of Australian and Chinese women. Methods: A pilot comparison study was carried out using modified valid menstrual questionnaires. The study included 120 Australian women and 122 Chinese women aged from 18 to 45 years with primary dysmenorrhea. Results: Australian women rated menstrual pain as more intense than Chinese women (8.5 ± 1.5 on a 10-point pain scale vs 7.3 ± 1.8, P < 0.001), duration of pain was 36% longer (3.0 ± 2.5 vs 2.2 ± 0.9 days, P = 0.002) and menarche commenced earlier (12.7 ± 1.5 vs 14.2 ± 1.4 years, P < 0.001). The mean reported menstrual interval was also shorter (29.2 ± 5.3 vs 30.52 ± 3.7, P = 0.020) with heavier overall menstrual flow (P = 0.002) and fewer clots in menstrual blood (83% vs 95.8%, P = 0.001). There was no significant difference in duration of menstruation (5.2 ± 1.3 vs 5.4 ± 1.1 days; P = 0.180). Correlations were found between earlier menarche and increased intensity of menstrual pain (r = -0.16, P = 0.011), and between heavier menstrual flow and increased intensity of menstrual pain (r = 0.19, P = 0.003). Conclusion: Evidence from this pilot study suggested that the clinical menstrual presentations in the cohorts of Australian and Chinese women were different. Although the findings are preliminary, evaluating ethnic differences in menstruation and experimental menstrual pain models may not only provide some information about underlying mechanisms but may also predict or explain group differences.