作者单位:Ludwig Maximilians University of Munich, Department of Obstetrics and Gynaecology, Maistrasse 11, D[1]Ruprecht-Karls University of Heidelberg, Department of Gynecological Endocrinology and Fertility[2]University Hospital Jena, Department of Obstetrics, Placenta Laboratory, Bachstrasse 18, D-07743[3]