[1] Univ Technol Sydney, Fac Hlth, Australian Ctr Publ & Populat Hlth Res, Sydney, NSW, Australia
[2] Macquarie Univ, Fac Med & Hlth Sci, Sydney, NSW, Australia
[3] Royal Brisbane & Womens Hosp, Dept Cardiol, Brisbane, Qld, Australia
[4] Queensland Univ Technol, Australian Ctr Hlth Serv Innovat, Brisbane, Qld, Australia
[5] Australian Natl Univ, Med Sch, Dept Obstet & Gynaecol, Coll Hlth & Med, Canberra, ACT, Australia
[6] Canberra Hosp, Centenary Hosp Women & Children, Dept Obstet, Canberra, ACT, Australia
[7] Univ Queensland, Royal Brisbane & Womens Hosp, Dept Obstet & Gynaecol, Womens & Newborn Serv, Brisbane, Qld, Australia