Theodoros Maltaris1,2
, Michael Weigel2
, Andreas Mueller3
, Marcus Schmidt1
, Rudolf Seufert1
, Franz Fischl1
, Heinz Koelbl1
and Ralf Dittrich3 
1Department of Obstetrics and Gynecology, Johannes Gutenberg University, Mainz University Hospital, Langenbeckstr. 1, 55124 Mainz, Germany
2Department of Obstetrics and Gynecology, Leopoldina Hospital, Gustav-Adolf-Str. 8, 97421 Schweinfurt, Germany
3Department of Obstetrics and Gynecology, Erlangen University Hospital, University of Erlangen-Nuremberg, Universitaetsstr. 21–23, 91054 Erlangen, Germany