Could a lower dose of birth control mean you have a higher risk of pregnacy?

Effective: It wouldn't make sense if the Food and Drug Administration (FDA) would allow a birth control pill to be distributed, if it did not meet established criteria for effectiveness. There is a small risk for women to get pregnant on any birth control pill. However, it is not the dose that makes the difference, but how well an individual woman does or does not adhere to prescription instructions.