New concepts in oral contraceptive pill use.

Over 30 years have elapsed since the introduction of the combination oral contraceptive pill. During this time, the estrogen and progestogen components of the pill have been reduced 80% and 90%, respectively. An improved understanding of the mechanisms involved in the metabolism of the oral contraceptive pill steroids now exists that allows us to better understand interactions of the pill with other drugs and medications. In an effort to reduce adverse reactions to the oral contraceptive pill, new progestogens have been developed for contraceptive pills soon to become commercially available. These issues as well as the concept of the pill-free interval are discussed in this review.