What Are The Side Effects Of Using Microgynon 30?

hi i am 18 and have been talking microgynon 30 for quite a few months now, but i have recently noticed that i have spots of blood in my dischrage but only abit, it is odourless though, i read that it can be due to taking your pill at different times, and i have suddenly changed from taking it in the morning to taking it at night now. but i just want to clarify it is this and not anything else like pregnancy or cancer