Authors’ contributions:
S. Tebeka drafted the initial manuscript, and approved the final manuscript as submitted.
J. Mullaert carried out the initial analyses, revised the manuscript, and approved the final manuscript as submitted.
C. Dubertret designed the study, revised the manuscript, and approved the final manuscript as submitted.
A. Benachi, M. Dommergues, C. Dubertret, D. Luton, and L. Mandelbrot created and validated the questionnaire on obstetric characteristics.
A. Benachi, M. Dommergues, G Kayem, Y. Le Strat, J. Lepercq, D. Luton, L. Mandelbrot, Y. Ville, and N. Ramoz, revised the manuscript, and approved the final manuscript as submitted.
Details of Ethics Approval: The research protocol (ClinicalTrials.gov Identifier: NCT01648816), including informed consent procedures, was approved by the French Ethics committee (Ile de France I) on March 2011 (reference numbers: AOM10056, NI10018, IGEDEPP, ID-RCB 2010-AO1315-34) and Data Protection and Freedom of Information Commissions.
Funding: The study was funded by a grant from Programme Hospitalier de Recherche Clinique - PHRC 2010 (French Ministry of Health). The sponsor was Assistance Publique – Hôpitaux de Paris (Délégation à la Recherche Clinique et à l’Innovation).