This study shows how reform in the Peruvian health system has increased physician incentives in the private sector to overuse cesarean sections. C-section rates in the private sector grew from 27% to 48% after the health reform, while the rates remained constant at 19% in the public sector. Based on a national survey and on a new methodology to estimate overtreatment, this study quantifies the number of women who had cesarean sections for non-medical reasons. The estimation considers the impact of clinical and nonclinical variables on health outcomes, and separates out non-medical factors to define a guideline for clinically appropriate c-sections. It is estimated that yearly, more than 13 thousand women have a c-section without medical reasons. The number of unnecessary c-sections has grown considerably in the private health care sector after the reform. This document highlights the consequences of unnecessary c-sections on women’s reproductive rights, and establishes important implications and recommendations for other health reforms in Latin America.