Where do the excess embryos go?

BY BETH WHITEHOUSE | beth.whitehouse@newsday.com

In any in vitro fertilization procedure -- whether to help with infertility, to screen embryos for inherited disease or to select an embryo as a tissue match for a sick sibling -- more viable embryos are often produced than needed to create a single baby.

In those cases, the couple chooses what to do with the excess embryos. They can discard them, donate them to research or to another couple or freeze them for possible use in the future.

Freezing embryos -- also known as cryopreserving -- puts them in suspended animation and delays a decision about what to ultimately do with them.

Fertility experts say many couples return to a reproductive endocrinologist to have another child and thaw out their frozen embryos to get pregnant. In those cases, freezing is advantageous, as getting pregnant with frozen embryos is less invasive and less expensive than undergoing another cycle of egg retrieval to create new embryos, said Dr. Avner Hershlag, director of the PGD program at North Shore University Hospital's Center for Human Reproduction in Manhasset.

But for couples who have had as many children as they want, the decision hangs over them, sometimes for years.

In 2002, the national Society for Assisted Reproductive Technology surveyed the nation's 430 IVF clinics to get an idea of how many embryos were frozen in the United States. The estimate, garnered from the 340 clinics that responded: 400,000.

Long Island IVF, based in Port Jefferson, participated in the survey. At that point, Long Island IVF had 4,000 embryos stored in its lab, said Dr. Daniel Kenigsberg, co-director of the program. By the end of 2005, the number had increased to 5,550 stored, he said.

But those aren't necessarily the same embryos. Frozen embryos are constantly being thawed and used and replaced by newly frozen embryos, Kenigsberg and other area doctors said. For example, in 2005, 1,663 embryos were frozen by Kenigsberg's lab, and 1,641 were thawed.

Of those thawed, 46 percent were used to attempt another pregnancy, and produced approximately 100 babies, Kenigsberg said. Twenty percent were donated to research and 2 percent were donated to another couple. In 32 percent of the cases, the embryos were discarded.