Note: Funding Information: The OPTIMIST study was funded by The Netherlands Organisation for Health Research and Development (ZonMW number 171102020). Funding Information: T.C.T., H.L.T. and S.C.O. received an unrestricted personal grant from Merck BV. B.W.J.M. is supported by a NHMRC Practitioner Fellowship (GNT1082548) and reports consultancy for OvsEva, Merck and Guerbet. F.J.M.B. receives monetary compensation as a member of the external advisory board for Ferring pharmaceutics BV (the Netherlands) and Merck Serono (the Netherlands) for consultancy work for Gedeon Richter (Belgium) and Roche Diagnostics on automated AMH assay development (Switzerland) and for a research cooperation with Ansh Labs (USA). M.J.C.E. has nothing to declare. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.