Funding for this research was provided by:
AXA Research Fund
Received: 17 March 2017
Accepted: 30 May 2018
First Online: 28 June 2018
Ethics approval and consent to participate
: The data for this analysis were collected in the ProTwin trial (NTR1858), reported in detail elsewhere data.The ProTwin trial received ethics approval from the Medical Ethics Committee of the Academic Medical Centre of the University of Amsterdam, The Netherlands (MEC O9/1O7), and received approval for local execution, in line with the Dutch legal requirements for research in humans, from all other participant center. All participants provided written informed consent prior to study entry and were aware that the data they contributed were used to analyze the effect of a pessary on pregnancy outcome in multiple pregnancies. The full names and affiliations of the AMC ethics committee are provided in the “AMC Medical Ethics Committee Approval_ProTWIN” letter which can be accessed at the trial website ExternalRef removed .
: We declare that we have no competing interest.
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