HI, thanks for choosing HCM no dear reason for not getting periods may not be due to metformin metformin is used to reduce insulin resistance it also helps to reduce your weight through this process delay in periods is due to anovulation (no egg production ) or oligo ovulation(less egg production) mainly due to hormonal imbalance that occurs in pcos so you need regular treatment first get a scan done, get a view on the extent of the problem go for oral contraceptives to regularise cycles,and clear hormonal imbalance pcod is a pre diabetic state ,get proper blood tests done take treatment you may proceed with metformin remember weight loss of nearly 5 kgs can regularise your periods without need of medication generally so meet your doctor ,take proper and regular treatment after that go for scan once again and when your condition improves you may stop the treatment remember pcos may recur many times so even after cure you need to manage your weight and follow good diet and exercise wish you good luck hope i answered all your queries feel free to contact me for further queries thank you