What should i expect when one stops taking the birth control pill after being on it for a year and a half?

Sometimes nothing: Sometimes when women stop taking they don't notice anything. Sometimes they might notice 1) changes in breast size or texture; 2) lengthening of their period, heavier periods; 3) increased sex drive (or decreased if you're afraid of getting pregnant); 4) changes in chair texture or amount; 5) weight gain or loss. Those are just a few of the more common ones. You may have some or none. Goodluck.