1. Obstetrics and Gynaecology Department , Complexo Hospitalario Universitario de Ourense , Ourense , Spain
2. Analytical and Food Chemistry Department , Nutrition and Bromatology Group, Agri-Food Research and Transfer Cluster (CITACA), Campus da Auga, Faculty of Sciences of the University of Vigo , Ourense , Spain
3. Statistical Studies , Official College of Physicians , Ourense , Spain