1 Department of Obstetrics and Gynecology, Lyell McEwin Hospital, University of Adelaide, Australia; Department of Obstetrics and Gynecology, University Medical Center Groningen and the University of Groningen, The Netherlands.
2 Department of Obstetrics and Gynecology, University Medical Center Groningen and the University of Groningen, The Netherlands.
3 Department of Epidemiology, University Medical Center Groningen and the University of Groningen, The Netherlands.
4 School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia.
5 Department of Obstetrics and Gynecology, Lyell McEwin Hospital, University of Adelaide, Australia.