I have irregular periods, its always late, sometimes its 2 month late, sometime 1month, 15days late. will birth control pill results weight gain?

not likely: Most women who start birth control pills or other methods of birth control don't have side effects.The most common one for pills is irregular bleeding for the first 1-3 months; other methods like the shot are more likely to cause irregular bleeding at least at first.Other side effects can be nausea, headaches, mood changes, breast tenderness.Most women don't gain weight with the pill.