Combined oral contraceptive (COC)

Effectiveness depends on the user. It is 99.9% effective if used correctly and consistently. This means that less than one woman in 1,000 using combined oral contraceptives correctly and consistently will become pregnant in the first year of use. Correct use means not missing any pills, and taking extra contraceptive precautions if that happens. Risk of pregnancy is greatest when a woman starts a new pill pack three or more days late, or misses three or more pills near the beginning or end of a pill pack.