1 Department of Obstetrics and Gynaecology, National University Hospital Singapore, Kent Ridge, Singapore. Electronic address: nur_azleen_sidek@nuhs.edu.sg.
2 Department of Obstetrics and Gynaecology, National University Hospital Singapore, Kent Ridge, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Kent Ridge, Singapore.
3 Department of Obstetrics and Gynaecology, National University Hospital Singapore, Kent Ridge, Singapore.