1Department of Obstetrics and Gynecology, Hyvinkää Hospital, Hospital District of Helsinki and Uusimaa, Hyvinkää, Finland2Department of Obstetrics, Gynecology and Neonatology, The Queen Elizabeth II Research Institute for Mothers and Infants, University of Sydney, Sydney, New South Wales, Australia3Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Helsinki, Finland