Reply of the Authors: Fresh vs. frozen embryo transfer: new approach to minimize the limitations of using national surveillance data for clinical research
1 Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
2 Division of Public Health Sciences, Washington University School of Medicine in St. Louis, St Louis, Missouri.
3 Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
4 Department of Gynecology and Obstetrics, Emory University School of Medicine, Atlanta, Georgia; Department of Biostatistics and Bioinformatics, Emory University School of Public Health, Atlanta, Georgia.