There are no specific side effects to coming off the pill, though you may be aware of some changes in your body when you do stop using it.
While on oral contraceptives, the natural menstrual cycle is replaced by cycles that are regulated by the hormones in the pill. Cycles produced by the pill tend to be more regular, lighter, and less crampy than natural cycles. When you stop the pill and return to your normal cycles, you may notice this difference.
You can stop taking the pill suddenly without danger. However, if you stop in the middle of a cycle it is likely you will experience some irregular bleeding until the effects of the pill clear from your system. This may last a few weeks.
In addition to providing effective protection from pregnancy, the pill offers other benefits. Many women on the pill have less acne, less severe PMS symptoms, and fewer ovarian cysts. These benefits are present only while the pill is being used. If any of these conditions are present before starting on the pill, they are likely to return when you stop taking the pill.