a b s t r a c t Study Objective: To study the effectiveness of performing Zumba exercise on the severity and duration of pain in patients with primary dysmenorrhea. Design: Randomized controlled trial. Setting: Cairo University gynecology Hospital and Bahgat gym and fitness center. Participants: Ninety-eight women diagnosed with primary dysmenorrhea. Interventions: Study participants were divided randomly into 2 equal groups: group I included women who engaged in Zumba exercise for 60 minutes twice weekly for 8 weeks, and group II was a control group with no intervention. Main Outcome Measures: The primary outcome was the menstrual pain intensity measured using the visual analogue scale scores at 4 and 8 weeks after starting Zumba exercise. The secondary outcome was the difference in the duration of pain in both groups. Results: Both groups were homogeneous regarding the baseline demographic characteristics. The severity of primary dysmenorrhea at the beginning of the study was not significantly different between the 2 groups. Menstrual pain intensity was significantly decreased in the Zumba group after 4 and 8 weeks of Zumba compared with the control group (mean difference,
2.94 [95% confidence interval,
3.39 to
2.48] and
3.79 [95% confidence interval,
4.16 to
3.43], respectively; P 5 .001). Also, the duration of pain was shorter in the Zumba group compared with the control group at 8 weeks (4.92  1.90 vs 9.10  2.92 hours, respectively; P 5 .001). Conclusion: The Zumba intervention can reduce the severity and duration of menstrual pain thus suggesting that regularly performing