Miscarriage clues identified in new DNA test

The technique used in this study, called rescue karyotyping, allows physicians to obtain important genetic information from tissue that had not been tested at the time of the miscarriage. As part of standard hospital protocol, tissue from miscarriages is embedded in paraffin for archival use and the karyotyping test is performed on DNA extracted from this tissue.

In this retrospective study of 20 samples from 17 women, genetic testing was successfully performed on 16 samples that had been archived for as long as four years. Of those samples, eight showed chromosomal variants and abnormalities. This is an important alternative when conventional karyotyping is not available or cannot be used for a specific sample.

"Given the ease of obtaining results, even if a delay in testing occurs, this new test may provide a useful technique to gain a better understanding as to why miscarriage occurs in some women," said Zev Williams, M.D., Ph.D., director, Program for Early and Recurrent Pregnancy Loss (PEARL), Montefiore and Einstein, assistant professor of obstetrics & gynecology and women's health and of genetics at Einstein, and corresponding author of the study. "I have seen women in tears because testing was not done at the time of the miscarriage and they feared they would never learn why it happened. Now we are able to go back and often get the answers we need."

One in five pregnancies ends in miscarriage, with the vast majority occurring in the first trimester. Recurrent miscarriage, which is defined as two or more miscarriages, occurs in up to 5 percent of couples attempting to conceive. Led by Dr. Williams, PEARL is made of a team of expert physicians, scientists, genetic counselors, nurses, technicians and staff members who work together to help these women maintain their pregnancies.

"Montefiore and Einstein have worked together to develop an innovative model based on research, which allows us to create novel diagnostic and treatment options and, in parallel, to quickly bring new advances to the clinic," said Dr. Williams. "This represents a new and emerging model in medicine -- where the lab and clinic are brought closer in order to speed the pace of discovery and treatment."

"Most miscarriages are caused by an abnormal number of chromosomes in the embryo, accounting for up to 75 percent of first trimester losses," continued Dr. Williams. "This new test can help guide future treatment options but, more importantly, can also help alleviate some of the guilt and self-blame often associated with unexplained miscarriage and can close a door on a painful chapter in a woman's and couple's life."