Received: 18 November 2019
Accepted: 25 April 2020
First Online: 6 May 2020
Compliance with ethical standards
: Potential conflicts of interest: A. Germeyer—Director of the board of Fertiprotekt e.V. No potential conflicts of interest with direct of potential influence or bias on the work: M. Goeckenjan, A. Freis, K. Glaß, J. Schaar, I. Trinkaus, S. Torka, and P. Wimberger.
: The study protocol was approved by the local ethics committee. All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study (EK 314072015).