thank you for asking HCM
I have gone through your query. Your problem can be due to constipation
during starting of periods. Taking vegetables and fibres and more plain water may help you. Stool softeners like lactulose
can be used. Avoid coffee and excess tea on that time. If all these not helping then consult your gynecologist for per vaginal examination. Hope this may help you.
Let me know if you have any further queries.