[1] Royal Hosp Women, Randwick, NSW, Australia
[2] Univ Sydney, Childrens Hosp, Westmead Clin Sch, Child Populat & Translat Hlth Res, Camperdown, NSW, Australia
[3] Univ Sydney, Menzies Ctr Hlth Policy & Econ, Camperdown, NSW, Australia
[4] Univ New South Wales, Fac Med & Hlth, Sch Populat Hlth, Kensington, NSW, Australia
[5] Univ New South Wales, Darlinghurst, NSW, Australia
[6] Australia & St Vincents Hosp, Darlinghurst, NSW, Australia
[7] Univ Iceland, Fac Med, Ctr Publ Hlth Sci, Reykjavik, Iceland
[8] Nepean Hosp, Perinatal Unit, Kingswood, NSW, Australia