What is the best approach to reducing birth defects associated with isotretinoin?

Isotretinoin is an effective treatment for severe acne, a condition which can be physically, emotionally, and socially disabling. Because the drug is teratogenic, causing severe birth defects, women taking the drug are directed to avoid pregnancy. In the United States, a series of risk reduction programs have been implemented that aim to prevent pregnant women from taking the drug and to prevent women taking it from getting pregnant. The most recent, and most stringent, is an Internet-based, performance-linked system called iPLEDGE, which tries to ensure that the drug is dispensed only when there is documentary proof that the patient is not pregnant and is using two forms of birth control. Is iPLEDGE the best way to reduce isotretinoin birth defects, or is it an unproven and overly burdensome system?