Twenty percent of all pregnancies end in miscarriage and recurrent miscarriage happens to about 5% of all couples trying to have a family. It's always a painful experience that can be especially heartbreaking when there is no apparent reason for it. Unexplained miscarriage can leave a couple wondering if it will happen again or what they could have done differently.

In most cases, there's nothing that could have been done differently. About 75% of all first trimester miscarriages are caused by chromosomal abnormalities. When a miscarriage occurs, tissue samples are taken and archived but they aren't always tested for the cause. The bereaved couple remains mystified.

Now, however, researchers have discovered a way to test archived tissue samples to determine long after the event if the miscarriage was caused by chromosomal abnormalities. The test — rescue karyotyping — found chromosomal variations and abnormalities on archived tissue from miscarriages that had occurred as far back as four years.

The term, karyotype, refers to the number of chromosomes in the nucleus of a cell and their appearance. When a karyotyping examination is done, it reveals the health of the cell. When karyotyping is done at the time of miscarriage, the reason for the event can often be identified and future plans can be made accordingly.

Zev Williams, director for the Program for Early and Recurrent Pregnancy Loss (PEARL) at the Montefiore Medical Center in the Bronx and the Albert Einstein College of Medicine at Yeshiva University in New York City, used archived tissue samples to see if rescue karyotyping could bring answers to patients who never learned why miscarriage occurred. In 50% of the cases that his research team examined, abnormalities and variations in chromosomes that could cause miscarriage were identified.

The PEARL study examined 20 tissue samples taken from 17 women at the time of miscarriage. Sixteen of the samples had been archived for an extended period of time, as long as four years. Genetic variations were discovered in eight of the longest-archived samples.

"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," said 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."

Source: Williams, Zev, et al. "Rescue karyotyping: a case series of array-based comparative genomic hybridization evaluation of archival conceptual tissue." Reproductive Biology and Endocrinology. BioMed Central Ltd. Mar 3, 2014. Web. Mar 23, 2014.