1 Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR; OHSU-PSU (Oregon Health & Science University-Portland State University) School of Public Health, Portland, OR.
2 Institut des Sciences de l'Evolution de Montpellier, Montpellier University, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, Montpellier, France; School of Anthropology and Museum Ethnography, University of Oxford, Oxford, UK.
3 Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR; OHSU-PSU (Oregon Health & Science University-Portland State University) School of Public Health, Portland, OR; Instituto Nacional de Salud Pública, Centro de Investigación en Salud Poblacional, Cuernavaca, Morelos, México.
4 Natural Cycles Nordic AB, Stockholm, Sweden.
5 Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR. Electronic address: edelmana@ohsu.edu.