1. Department of Obstetrics and GynaecologyThe Royal Women's Hospital, The University of Melbourne Parkville Victoria Australia
2. Department of Maternal Fetal MedicinePregnancy Research Centre, The Royal Women's Hospital Parkville Victoria Australia
3. Ultrasound ServicePauline Gandel Women's Imaging Centre, The Royal Women's Hospital Parkville Victoria Australia
4. Department of AnaesthesiaThe Royal Women's Hospital Parkville Victoria Australia
5. Department of Medicine and RadiologyThe University of Melbourne Parkville Victoria Australia
6. Department of Pharmacology and TherapeuticsThe University of Melbourne Parkville Victoria Australia
7. Department of Obstetrics and GynaecologyMonash University Clayton Victoria Australia
8. Departamento de Ginecologia e ObstetriciaHospital das Clinicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo Ribeirão Preto Estado de São Paulo Brazil