The study was erroneously registered as an interventional trial on ClinicalTrials.gov between 2010 and 2012. It was shown recently that the study protocol and conduct of the study did not include any clinical interventions beyond those which are Standard Clinical Practice and the approved label for Gonal-f®. Furthermore, all other relevant study essential documentations (e.g. Informed Consent, CRF, etc.) are in line with an observational study design. As per EU regulations (Article 2(c) of Directive 2001/20/EC), this study is a 'non-interventional trial'.