Why does Spironolactone cause irregular menstruation? Is it safe for family history of breast cancer?

How does Spiro affect each sex hormones? I took 200 mg Spironolactone for hair loss/hirsutism for 10 years with very good success. I stopped the drug bc I read that it disrupts estrogen metabolism. The irony is that while on Spiro I had very few/light periods and no breast pain. Off of Spiro I have pretty bad breast and period pain. If breast pain/painful periods are associated with poor estrogen metabolism it seems that perhaps Spironolactone had some protective effects in my case?