Hi,I had gone through your query and appreciate your concern. I guess that you are taking diclofenac because of premenstrual and menstrual pain.Be sure that you are taking Ranitidine or proton pump inhibitor(example:omeprazole) like drugs along with diclofenac. Most of the pain killers specially NSAIDs (diclofenac) should use with caution for a short period of time because of its adverse effects like abdominal bloating,belching,gastric and intestinal bleeding etc. If I were your physician ,I would ask you for your menstrual history like regular or irregular,duration and quantity of bleeding etc. If above queries are normal ,you need not to worry.It is normal that your menstrual bleeding will not be same all the time.The possibility of having any effect of diclofenac on mentrual bleeding is very low. Hope this answers your query. Wish you good health.