The aim of this protocol is to study the deleterious impact of adjuvant chemotherapy or neoadjuvant chemotherapy on ovarian reserve in young women suffering from breast cancer. A new relevant ovarian reserve marker, serum Anti-Mullerian Hormone, will be used in order to evaluate precisely the impact of chemotherapy on ovaries during chemotherapy administrations and after during follow-up (24 months). This strategy offers 2 main advantages : no modification of the traditional care of patients (treatment, organisation, follow up …) and use of a non invasive marker (serum). The final objective is to give precise information to patients on their future fertility after remission.