IVF Failure Similar to Transplant Rejection, Experts Say
Fertility experts are making headway in understanding why more than half of all IVF treatments fail – a major source of financial and emotional loss for couples struggling with infertility.
According to infertility researchers from the Center for Human Reproduction (CHR) in New York, failed IVF treatments may be a result of a mother's immune rejection of the embryo during implantation – similar to that of a rejected organ transplant.
During an IVF procedure (in vitro fertilization) a woman's egg and a males' sperm are fertilized together in a laboratory setting to form an embryo. The resulting embryo is then tested for abnormalities or other risk factors that may indicate that it may not create a viable pregnancy. Once the health of the embryo is established it is then transferred back into the uterus of the mother where it implants itself into the lining for the duration of the pregnancy. Without successful implantation – a pregnancy does not occur.
Unfortunately, despite healthy embryos more than half of all women who undergo IVF procedures still fail to become pregnant. For infertility treatment providers, identifying this cause has been one of the industry's biggest challenges
"If there are abnormal embryos, there is nothing we can do about that," said Alan Handyside, director of the London Bridge Fertility Centre in an interview with ABC news. "This is ultimately about identifying [patients at risk for IVF failure] and preventing women from going through the stress of multiple failed IVF cycles."
In searching for an explanation for why healthy embryos fail to create pregnancies in IVF treatments, Dr. Norbert Gleicher, the CHR's medical director, and his team of researchers began studying how autoimmunity affected implantation of an embryo.
“Implantation is an immunologic process,” explained Gleicher. “Because the genetic material of the implanting embryo is half paternal, for the mother’s immune system, the embryo is analogous to an organ transplant. Under normal circumstances, however, this ‘transplant’ is not rejected.”
According to their study, women who experience IVF failures have higher rates of autoimmune disease – a finding that suggests perhaps the mother's immune system attacks an embryo when it tries to implant itself rather than accept the pregnancy. Furthermore, the researchers were able to identify specific genes they believe to be responsible for this rejection.
“We now have evidence that IVF outcome differences... are likely immunologic in nature,” says Dr. David H. Barad, Clinical Director at the CHR. The ability to be able to make a genetic test to identify the likelihood of a failed implantation, the researchers say, may be the key to helping physicians identify which patients are ideal candidates for IVF procedures.
In addition, Gleicher adds, “these prognostications may open up revolutionary new avenues to therapies to improve implantation and IVF pregnancy chances through immunologic treatments.”
IVF NY Center for Human Reproduction
Gleicher N, Weghofer A, Lee IH, Barad DH (2010) FMR1 Genotype with Autoimmunity-Associated Polycystic Ovary-Like Phenotype and Decreased Pregnancy Chance. PLoS ONE 5(12): e15303. doi:10.1371/journal.pone.0015303