Washington: Researchers have developed the first genetic blood test for predicting the chances that in vitro fertilization (IVF) will lead to a successful pregnancy.
The test is based on the finding that different subtypes of the FMR1 gene (also known as the fragile X mental retardation gene) in potential mothers are associated with significantly different chances of conceiving with IVF.
"This is the first evidence that a specific gene appears to be directly associated with IVF outcomes," said David Barad, one of the study``s senior authors.
"Our research also suggests the FMR1 gene, some forms of which are known to predict premature ovarian failure, could be used to predict at what age a woman`s fertility is going to start decreasing," he said.
The study has also supported the belief that autoimmunity (immunity to one`s own cells or tissues) plays a role in infertility-a controversial topic among reproductive medicine specialists.
The study involved 339 female infertility patients who underwent a total of 455 IVF cycles at CHR. The researchers investigated the relationship between three different FMR1 genotypes and pregnancy outcomes and autoimmunity levels.
Women with the "normal" FMR1 genotype had a 38.6 percent pregnancy rate; those with the "heterozygous-normal/high" genotype had a 31.7 percent pregnancy rate; and women found to have the "heterozygous-normal/low" genotype had a 22.2 percent pregnancy rate.
The genotype associated with the lowest pregnancy rate was also associated with increased measures of autoimmunity.
Women with this genotype also had a higher incidence of polycystic ovary syndrome (a common cause of infertility), which is thought to have an autoimmune component.
"Previous studies have suggested that autoimmunity plays a role in infertility. Now, for the first time, we have a potential genetic mechanism that underlies several different threats to infertility," said Barad.
The cost of the blood test for the FMR1 should be relatively low - comparable to screening tests for Tay-Sachs and other genetic diseases.
"Any test that is proven to have predictive value for a woman``s fertility would give her a heads up in terms of planning a family," he added.
The findings were reported in the online medical journal PLoS One.