Prevalence of primary dysmenorrhea in Canada.

OBJECTIVE: The aim of this study was to describe the prevalence, clinical effect, characteristics, and underlying risk factors of primary dysmenorrhea (PD) in Canada.

METHODS: A stratified, random sample of 2721 women 18 years and older was identified, and the women were interviewed by telephone. Data about menstrual symptoms and patterns and socio-demographic factors were obtained. The frequency, severity, and effect of menstrual pain were quantified. Logistic regression analysis was performed in order to identify independent risk factors for PD.

RESULTS: In the sample, 1546 women were having menstrual periods; of these, 934 (60%) met the criteria for PD. Sixty percent of the women with PD described their pain as moderate or severe. Fifty-one percent reported that their activities had been limited, and 17% reported missing school or work because of PD. The prevalence of PD decreased with increasing age (P < 0.001) and increased with smoking (P = 0.002). Users of oral contraceptives (OCs) tended to have less pain than non-users (P = 0.005). Socio-economic status, nulliparity, and earlier age at menarche were not independently associated with PD. However, nulliparous women, smokers, and women not using OCs were more likely to report disabling symptoms.

CONCLUSIONS: The majority of Canadian women will suffer from dysmenorrhea at some time during their reproductive years. Available prescription treatments are underused. Young age, smoking, and non-use of OCs are independent risk factors for PD.