On yaz (drospirenone and ethinyl estradiol) pill skipped period but got period 2weeks later on white pills. why?

Missed pills?: Bleeding usually occurs when the hormonal levels drop. Theoretically, if you take the pills at the same time everyday and never miss a pill, your hormone levels should stay the same and so you should not bleed. But in reality, there is a standard distribution of people in the population for whom 'normal' does not apply and there is variability.