1 Department of Obstetrics and Gynecology, National University Hospital, Singapore. Electronic address: pradip_dashraath_vijayakumar@nuhs.edu.sg.
2 Department of Obstetrics and Gynecology, National University Hospital, Singapore.
3 Department of Obstetrics and Gynecology, National University Hospital, Singapore; Department of Obstetrics and Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Rd., NUHS Tower Block, Level 12, Singapore 119228.