Hi I think you are taking treatment for epilepsy from childhood. Are you having any other medical problems like thyroid ,pcos etc. Scan alone will not help in confirming the cause for irregular periods. You need to undergo certain hormone analysis like thyroid,prolactin ,and may be fsh and lh. sometimes your gynaecologist will give medicines to regularise your periods with out hormone analysis and if it doesnt correct it ,can go for hormone analysis. so visit a gynaecologist and take her opinion. I hope you are convinced. All the best.