Material and Method: A double blind, randomized, placebo-controlled trial was conducted in 80 patients with indication for endometrial biopsy at Ramathibodi Hospital between April 2013 and January 2014. The patients were randomly allocated into two groups to receive naproxen 500 mg (n = 40) or placebo (n = 40), 30 minutes before endometrial biopsy. Pain score was assessed using Visual Analogue Scale during and 10 minutes after the procedure. Adverse events were observed.

Results: The mean pain score during endometrial biopsy in the treatment group was significantly lower compared to the placebo group (5.11±0.18 vs. 6.49±0.17, respectively, p-value <0.001). However, the mean pain score at 10 minutes after endometrial sampling were minimal and had non-statistical significance in both groups. (0.60±0.56 vs. 0.59±0.64, p-value 0.971).

Conclusion: Naproxen 500 mg taken orally 30 minutes before endometrial biopsy significantly reduce pain score during the procedure.

Keywords: Endometrial biopsy, Naproxen, Pain score, Randomized controlled trial