I take metformin, how soon does my period go down?

I took metformin since 02/02/12, today is 12/02 my last menstruation was on 12/15/11 with the size of her delay, is it possible to ovulate in these days of delay? Day 10/02 came a blood stain the size of a big toe and has not come anymore, can this count as a menstruation? If not after how many days taking metformin does menstruation come from? Thank you very much in advance.
Expert answer:

You can ovulate (but it is harder) even if you do not have menstruation or it is irregular. Probably this little dirt can not be considered a menstruation.

Metformin is an auxiliary treatment in PCOS (Polycystic Ovarian Syndrome), it does not mean that metformin will make your menstruation go down or even regulate it.

Also read the article: Is Metformin a Good Treatment for Who Has Polycystic Ovaries?