Two-thirds of embryos created through in vitro fertilization (IVF) that are frozen and stored for more than 5 years end up being destroyed. During IVF, a woman's eggs are fertilized by a man's sperm in the laboratory. Then one or more embryos are implanted in the woman. In case the first attempt is not successful, embryos can be frozen and stored -- a technique called cryopreservation -- for use at a later time. Until 1995, embryos left unclaimed at fertility clinics in the United Kingdom could be destroyed only after 5 years, but that time has been extended to 10 years.

In the study, researchers tracked the fate of more than 1,300 embryos cryopreserved from 1988 to 1994 at two fertility clinics in Manchester, England. One of the clinics, a part of the National Health Service, provided fertility treatments free of charge, while the other charged fees for the services. Overall, 67% of embryos were destroyed -- 74% after couples failed to respond to letters sent from the clinics and 26% after couples gave instructions to destroy the embryos.

Cost may be a factor, according to the report, since couples treated at the fee-for-service clinic were much less likely to respond to the letters than patients at the free clinic.
The researchers also found that couples who had not been successful in having a baby were less likely than couples who had successful IVF to respond to letters from clinics asking whether they would like to keep their embryos in storage for an extended period of time.

The Lancet April 15, 2000;355:1336