1. Department of Obstetrics & Gynaecology; Westmead Hospital; Westmead NSW Australia
2. Faculty of Medicine, School of Women's & Children's Health; University of New South Wales; Sydney NSW Australia
3. Department of Obstetrics and Gynaecology; St George Hospital; Kogarah NSW Australia
4. Australian Centre for Perinatal Science; University of New South Wales; Randwick NSW Australia
5. Department of Maternal-Fetal Medicine; Royal Hospital for Women; Randwick NSW Australia