Study finds frozen embryo aids in-vitro fertilization

In-vitro fertilization babies who are conceived from frozen, rather than fresh, embryos have a remarkably better chance of survival than from the method most used in the past, according to a study by a Colorado physician who is considered one of the nation's leaders in reproductive medicine.

Dr. William Schoolcraft, of the Colorado Center for Reproductive Medicine in Lone-tree, says the scientific advancement has the potential to benefit thousands of Coloradans every year.

"For most couples, (in-vitro fertilization is) the difference between children and no children," he said.

In-vitro fertilization happens when eggs are removed from a woman's ovaries and fertilized with sperm, then implanted in the uterus to grow. The first healthy IVF baby was born in England in 1978. The procedure was introduced in the U.S. several years later, and in Colorado in 1982. Since then, more than 200,000 American babies have been conceived via IVF.

In Colorado, 1,800 babies were born via this procedure in 2011 alone.

Doctors have considered freezing the embryo before, but the process was not sophisticated enough. The new process, Schoolcraft said, has "changed everything."

The study, presented this fall to the American Society for Reproductive Medicine, showed that women ages 36 to 42 had a successful and safe birth rate of nearly 75 percent using the frozen method, compared with about 54 percent of patients who used fresh fertilized eggs.

"It's hard to wrap our arms around it," Schoolcraft said of the higher success rate. "For 20 years, we thought fresh was better and now we're seeing frozen is better."

The Colorado Center for Reproductive Medicine's study found that women using the frozen process carry the fetuses four to six days longer and have fewer miscarriages. In addition, parents can have chromosomal screening on the frozen embryo to detect birth defects.

Also, implanting a single frozen embryo means couples will have only one child per birth.

The previous school of thought was that women should produce eggs with the help of hormones, and then have the embryos implanted as soon as possible.

But using a frozen embryo is far less complicated. And, because couples don't need to become pregnant immediately, the process is often far more convenient for would-be parents.

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