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Mark Bush, M.D., Conceptions Reproductive Associates of Colorado

"We look at 150,000 points on the DNA from the mom, dad, and embryo. That typically allows us a 99 percent accuracy for each chromosome."

IVF and other assisted reproductive technologies have helped thousands of previously infertile couples conceive. As part of that process, pre-implantation genetic screening of the embryo looks for chromosome errors that can impact a couple’s chances of conceiving and delivering a healthy baby through IVF. “The screening is particularly important for women over 35, for women with a prior history of miscarriage or who have had an unsuccessful IVF cycle,” says Mark Bush, M.D., at Conceptions Reproductive Associates in Littleton.

Previous DNA screening techniques have been limited, only looking at seven to eleven chromosomes. But now, the newest and most advanced technology involves a microarray analysis that offers a look at all 23 chromosomes. “We look at the copy number across all of the chromosomes,” Bush says. “If you are over 35 and doing IVF, there will be abnormal chromosome numbers. A common abnormality is Down’s Syndrome with three copies of chromosome 21. Another is trisomy 16, which results in miscarriage.”

Statistically speaking, he says that if a woman over 35 has eight embryos, four have a high probability of having chromosomal errors. Because the new technology allows careful scrutiny of each of the embryos, it allows the doctor to narrow that down and then implant only 1 or 2 healthy embryos.

Dr. Bush performs an IVF egg retrieval at Conceptions' on-site IVF lab and center in Littleton, Colorado.

Bush says he’s always been interested in single embryo transfer. “If there are four DNA normal embryos, I will counsel to transfer one or two and freeze the others for transfer in the future. I’m not discarding healthy embryos or creating a risky situation for both mother and infants by transferring multiple embryos and running the risk of triplets. It is important to look at the Society of Assisted Reproductive Technology website (http://www.sart.org/) and review the number of embryos transferred by the IVF practice and the percentage of births that are triplets. For the last two reportable years, Conceptions’ triplet rate is 0 percent.”

This new process has been in a research phase for several years. “This technology is far superior than anything else out there for checking DNA,” he says. “The original DNA diagnosis was done in 1992 when they looked at the cystic fibrosis gene and were able to put back a non-afflicted embryo.”

Since then the technology has continued to be improved but there were still limitations. “The problem was the technology still only allowed a look at some of the chromosomes.”

Another technology that looks at all of the chromosomes is available in other areas of Colorado. “Comparative genomic hybridization (CGH) is less accurate than microarray analysis with Parental Support Technology and it takes five days to complete so the woman can not receive a fresh embryo transfer.”

The single nucleotide polymorphism microarray analysis technology, used by Conceptions, includes the addition of Parental SupportTM bioinformatics. It incorporates genetic data collected from the parents with a simple cheek swab and improves result accuracy.

“We look at 150,000 points on the DNA from the mom, dad, and embryo. That typically allows us a 99 percent accuracy for each chromosome.”

The test has rapid turnaround allowing a woman to have an embryo transfer in the same cycle that she undergoes IVF.

This technology has been greater than two years in the making in terms of being able to offer this to the general public, Bush says. Conceptions has partnered with Gene Security Network (GSN) to make it happen. GSN specializes in combining bioinformatic analysis with leading laboratory techniques to deliver highly accurate full-genome testing on small quantities of biological material. The Parental SupportTM is GSN’s proprietary testing technology. The company and its testing laboratory are based in Redwood City, California.

Conceptions is the only group in Colorado, and one of five leading IVF centers in the country, to first offer this cutting edge technology. As a leader in the field, Bush is board certified in both Obstetrics and Gynecology and Reproductive Endocrinology and Infertility. He has held the rank of Clinical Assistant Professor at the University of Washington School of Medicine in Seattle, Washington, and associate professor at the F. Edward Hebert School of Medicine in Bethesda, Maryland. Among his many awards is the American College of Obstetricians and Gynecologists CREOG National Faculty Award, which he received in 2001. He has been a partner at Conceptions for the last four years. Conceptions also has an office in Lafayette, Colorado. For additional information, log on to www.conceptionsrepro.com.