The authors would like to thank several people for helping in the construction of this review, namely Michelle Proctor, Review Group Coordinator of the Menstrual Disorders and Subfertility Group (MDSG); Ruth Buist for retrieval of trials and Sue Hall for helping to collect trials we needed and their positive support; Anne Lethaby for her statistical advice. We would also like to thank Dr M Merrilees and Dr MHJM. Curfs for their advice on laboratory techniques and A Vail and J Deeks for their advice on the statistical analysis. A special thanks to Dr WC Dodson, Dr R Menkveld and Dr P Prakash for putting such an effort into getting the information we asked for and for always replying to the numerous e‐mails we sent. Also a thank you is extended to Dr E Makrakis, Dr M Bajamonte, Dr J Check, Dr WCL Ford, Dr M Hammadeh, Dr A Menge, Dr M Morshedi, Dr A Oliva, Dr U Punjabi, Dr P Serafini, Dr C Srisombut, Dr B Storey and Dr L Werlin, who provided additional information on their trials.