Acknowledgements
We thank thousands of healthcare workers who have contributed to data collection at the provincial, city, township, and village levels. We appreciate Professor He-Feng Huang (Chairman of the Department of Reproductive Endocrinology, Women’s Hospital, School of Medicine, Zhejiang University at the time of the survey) for her coordination of the investigation in Zhejiang Province. We also thank Professor Canquan Zhou (Chairman of Chinese Society of Reproductive Medicine at the time of the survey) for his coordination and organization throughout the implementation of the project. Furthermore, we appreciate the efforts of Doctor Geng Yu during the preparation and execution phases of this study and express our gratitude to Doctor Elyssa Metas (Creighton University School of Medicine/Valleywise Health Medical Center, Phoenix, AZ, USA) for her help with editing this article for language. All individuals named in our acknowledgements provided consent and reported no conflict of interest.