Objective: To determine the prevalence of dysmenorrhea, impact on school attendance, academic performance, social activities and knowledge of treatment in Thai adolescents.
Design: Cross-sectional, descriptive study.
Setting: Nakhorn Pathom Ratjabhat University, Nakorn Patom, Thailand.
Subjects: A total of 789 women who were 1st and 2nd year students from Nakhorn Pathom Ratjabhat University, Nakorn Patom, Thailand.
Material and Method: Subjects were asked to complete the 35 items anonymous questionnaire handed out by the researchers. The questionnaire included data regarding the social data, menstrual pattern, severity and duration of menstrual pain, impact of dysmenorrhea on school attendance, academic performance and social activities. The methods, knowledge of pain relief and medications used to treat dysmenorrhea were
also asked.
Results: The prevalence of dysmenorrhea were 84.2%. The most common symptoms were stomach cramp (78.0%), backache (58.9%) and mood change (56.9%). Only 31 (4.7%) had severe dysmenorrhea. The factors associated with dysmenorrhea were age at menarche (p < 0.05) and body mass index (p < 0.05). More than 60% of dysmenorrheic women reported that their class concentration was affected, Paracetamol was the drug known to 98.8% of participants with dysmenorrhea that help to relief their dysmenorrhea.
Conclusion: Dysmenorrhea is a significant public health problem. It has an impact on academic activities. Most of the subjects know that Paracetamol is the drug that help to relief their symptoms.

Keywords: Prevalence, Dysmenorrhea, Thai adolescents