1. Department of Obstetrics and Gynecology, University Hospital Gregorio Marañón, 28009 Madrid, Spain
2. Health Research Institute Gregorio Marañón, 28009 Madrid, Spain
3. Maternal and Infant Research Investigation Unit, Alonso Family Foundation (UDIMIFFA), 28009 Madrid, Spain
4. Department of Public and Maternal and Child Health, School of Medicine, Complutense University of Madrid, 28040 Madrid, Spain
5. Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
6. Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain