1 Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom.
2 CNRS, École Normale Supérieure de Lyon, Laboratoire de Physique, Lyon, France.
3 Centro Materno Infantil Do Norte-Centro Hospitalar Universitário Do Porto, Porto, Portugal.
4 Centro Académico Clínico, Instituto de Ciências Biomédicas Abel Salazar, Centre for Health Technology and Services Research, Faculty of Medicine, University of Porto, Porto, Portugal.
5 Department of Obstetrics and Gynecology and Center on Human Development and Disability, University of Washington, Seattle, WA, United States.