[1] Inst Maternal & Child Hlth IRCCS Burlo Garofolo, WHO Collaborating Ctr Maternal & Child Hlth, Trieste, Italy
[2] LSHTM, Fac Epidemiol & Populat Hlth, Maternal Adolescent Reprod & Child Hlth Care Ctr, London, England
[3] Inst Maternal & Child Hlth IRCCS Burlo Garofolo, Neonatal Intens Care Unit, Trieste, Italy
[4] Univ Trieste, Dept Med Surg & Hlth Sci, Trieste, Italy
[5] Univ Verona, Dept Diagnost & Publ Hlth, Verona, Italy
[6] Inst Maternal & Child Hlth IRCCS Burlo Garofolo, Dept Paediat, Trieste, Italy