Europäische Datensammlung zur Präimplantationsdiagnostik seit 1999

About 25 years ago, preimplantation genetic diagnosis (PGD) was introduced as an alternative to prenatal diagnosis for the detection of monogenic, mitochondrial and chromosomal disorders. After IVF or (mostly) ICSI, either polar bodies, blastomeres or trophectoderm cells are biopsied from the oocyte or preimplantation embryo and tested using a molecular method. Unaffected embryos are selected for transfer to the uterus, thereby preventing termination of pregnancy. In 1997, the European Society of Human Reproduction and Embryology (ESHRE) PGD Consortium was formed as part of the ESHRE special interest group on reproductive genetics, in order to undertake a long-term study of the efficacy and clinical outcome of PGD. In December 1999, the first PGD Consortium report was published. Since then, 13 data collections have been published. Furthermore, for the most recent years (2013-2015), unpublished data have been collected from about half of all 121 (89 European) members of the PGD Consortium. Although not as much as before, legislation, regulation and service of PGD still strongly vary among European countries. This has led to patients crossing borders to seek care. In the early days, the pattern of indications was more or less a reflection of the genetic disorders requiring prenatal diagnosis. Interestingly, in a number of countries an increasing number of tests are performed for adult-onset diseases, showing that, in these cases, PGD seems more acceptable than prenatal diagnosis. The most important chromosomal indications for PGD are reciprocal translocations (both male and female carriers). It can be noticed that cleavage stage biopsy is very slowly replaced by blastocyst stage biopsy. There is a normal percentage of pregnancies that end in a miscarriage. The number of terminations of pregnancy is extremely low. About one in six pregnancies will result in the birth of a twin and the number of higher-order multiples is very limited. In a small number of cases, misdiagnoses have been reported.