What Causes Brown Spotting For Four Days While On Meprate To Induce Period When Diagnosed With PCOS?

My period Date was on Jan 25 .. Feb 25 I did not get periods I did scanning on Feb 28 came to know I have pcos my doctor said to take meprate10mg for 5 days twice. 4 days after I saw brown vagina discharge. Its been 4 days know still I am getting brown discharge spotting with no period blood..please help me the reason