Embryo disposition: the forgotten "child" of in vitro fertilization.

Cryopreservation of embryos is frequently employed in in vitro fertilization (IVF) practices because transfer of more than 3 embryos per cycle is not advantageous, and cryopreserved embryos offer fairly high pregnancy rates upon eventual transfer. Unfortunately, frozen embryos accumulate (approximately 4 per cycle). Thus, industrialized countries have developed laws or guidelines to govern their disposition, which may be disposal, or donation to medical research or to a recipient infertile couple. Worldwide, national regulations vary from eternal preservation to 10-year and 5-year preservation limits. The attitudes of couples who have undergone IVF range from almost parental concern for the embryos to regarding them as medical by-products--with little relationship to a couple's having a living child, in most studies. This paper describes disposition studies in various countries and couples' actions taken at time of disposition, with special detail on the problems involved in embryo donation to another couple.