Affiliation: | 1. Department of Obstetrics and Gynaecology, Queen Elizabeth Hospital, Hong Kong, China;2. Department of Obstetrics and Gynaecology, United Christian Hospital, Hong Kong, China;3. Department of Obstetrics and Gynaecology, Prenatal Diagnostic Laboratory, Tsan Yuk Hospital, Hong Kong, China Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong, China;4. Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Hong Kong, China;5. Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, China;6. Department of Obstetrics and Gynaecology, Prenatal Diagnostic Laboratory, Tsan Yuk Hospital, Hong Kong, China |