Inappropriate intervention and inequitable access are well known, but inadequately understood, issues in US perinatal care. Both are related to the structure of the perinatal system; this paper focuses on their connection with levels of care. Professional and regulatory policies and reform efforts (in conjunction with market forces) have shared a svstem of levels differentiated according to specialist 'and technblogich capacity. Expansion of "higher" levels has contributed to their excessive su~olv and discriminatow use. The concept of risk offers a justification for levels of care, but it also reflects the structure of levels. In order to address inappropriate intensity and stratified access, we must not just redefine concepts, we must also restructure levels of perinatal care.