[1] Univ Adelaide, Discipline Obstet & Gynaecol, Adelaide, SA, Australia
[2] Robinson Res Inst, Adelaide, SA, Australia
[3] Womens & Childrens Hosp, Dept Perinatal Med, Adelaide, SA, Australia
[4] South Australian Hlth & Med Res Inst, Adelaide, SA, Australia
[5] Univ Adelaide, Sch Publ Hlth, Adelaide, SA, Australia
[6] Womens & Childrens Hosp, Dept Neonatal Med, Adelaide, SA, Australia
[7] Flinders Univ S Australia, Dept Obstet & Gynaecol, Bedford Pk, SA, Australia