Embryos Discarded During IVF Create Stem ...(ilization. The findings suggest that ...),Health

The findings suggest that even early-arrested embryos (sometimes called dead embryos) may contain individual cells capable of growing and dividing, the researchers said. But the 0.6 percent success rate using early-arrested embryos is too inefficient to be practical.

It was much easier to derive stem cell lines from embryos that were slightly more developed. The success rate was 4.1 percent using embryos discarded five days after fertilization, and 8.5 percent using embryos that had reach the blastocyst stage at day five of their development.

These efficiency rates are similar to those of normal frozen embryos.

"Prior work had suggested that poor-quality embryos would only rarely yield stem cell lines, but we have shown that blastocyst-stage embryos are a robust source of stem cells," senior study author Dr. George Daley, associate director of the Stem Cell Program at the hospital and an associate professor of biological chemistry and molecular pharmacology at Harvard Medical School, said in a prepared statement.

More information

The U.S. National Institutes of Health has more about stem cells.

-- Robert Preidt

SOURCE: Children's Hospital Boston, news release, Jan. 27, 2008