It is perfectly safe to stop taking the contraceptive pill before completing the pack. However, if you were stopping it because you are changing your method of contraception or plan to become pregnant then the usual practice would be to complete your current pack. Stopping the pill midway through the cycle will result in an early withdrawal bleed, which is not harmful but might be inconvenient for you. Failure to complete the pack will not have any negative consequences for your reproductive system or your general health.