I Had My 4th Child At The Beginning Of February.

I had my 4th child at the beginning of February. Then had my tubes cit, clipped, and burned in april. I had to get on birth control pills after that because my periods were very heavy and painful. But now I am facing spotting in between periods (I'm on my 2nd week of pills after my period of the first pack of pills). What could be causing the spotting? I have had to had the LEEP procedure done before because I had precancerous cells on my cervix. Does the spotting have to do with the bilateral tubal or my cervix or ovaries? Thank you for your help.