[1] Univ Melbourne, Dept Obstet & Gynaecol, Royal Womens Hosp, Parkville, Vic, Australia
[2] Royal Womens Hosp, Dept Maternal Fetal Med, Pregnancy Res Ctr, Parkville, Vic, Australia
[3] Monash Hlth, Perinatal Serv, Clayton, Vic, Australia
[4] Monash Ultrasound Women, Clayton, Vic, Australia