R Béranger1, A A Chantry2. 1. Inserm U1085-IRSET, university Rennes 1, 9, avenue du Pr. Léon-Bernard, 35000 Rennes, France. Electronic address: r.beranger26@gmail.com. 2. Baudelocque midwifery school, AP-HP, Paris Descartes university, 75014 Paris, France; Inserm UMR 1153, obstetrical, perinatal and paediatric epidemiology research team (EPOPé), centre for epidemiology and statistics Sorbonne Paris Cité (CRESS), DHU risks in pregnancy, Paris Descartes university, 75014 Paris, France.