Number of embryos for transfer following in vitro fertilisation or intra-cytoplasmic sperm injection

Acknowledgements: We would like to thank the following for their contributions to the 2020 update. All staff at the editorial base of the Cochrane Gynaecology and Fertility Review Group; and in particular, Helen Nagels (Managing Editor) and Information Specialist Marian Showell, for help with the literature searches. Drs Jeanette MacKenzie, Evi Vogiatzi and Rik van Eekelen who provided peer review comments. We also thank all the authors who replied to our email queries about their study: Dr Elisabet Clua, Dr Maria Luisa López‐Regalado and Dr OM Abuzeid. We also thank the following. Zabeena Pandian, who was the lead author of the original review and two subsequent updates. Other co‐authors for their contribution in the previous versions: Allan Templeton, Ozkan Ozturk, Gamal Serour, and Jane Marjoribanks. Statistician Andy Vail (University of Manchester University, UK) for methodological advice.