[Children born from frozen embryos stored for 10 years -- analysis of 5 cases]

Faced with a scientific and legal debate on human embryo cryopreservation in Poland we show 5 documented clinical cases of successful thawing and transfer of embryos cryopreserved for a long period of time (8-11 years), resulting in successful delivery by the biological or the recipient mother. Cases described include patients with different infertility diagnoses, subjected to different hormonal stimulation treatments. Different oocyte fertilization methods were performed, and the obtained embryos were frozen after 2, 3 or 4 days of in vitro culture using methods employing various cryoprotective agents and freezing curves. As a result of performed thawing and transfer procedures normal, healthy babies were born. Our results are consistent with the international reports on successful long-term storage of embryos, (including the longest known period of over 19 years) resulting in no detectable reduction of the developmental potential after thawing. In light of data shown here, we do not see any medical or biological reasons for legally-regulated limitation of the period of frozen embryo storage. Moreover, if frozen, long-term stored embryos are not threatened by destruction and if prenatal adoption is a real, clinically documented option, we fail to see any reason for legal limitations of embryo cryopreservation in human infertility treatment.