Here's a technological advance sure to appeal to women in their 30s and 40s trying to get pregnant from their own eggs or from donor eggs. A new method of testing the viability of embryos produced via in vitro fertilization (IVF) more than doubles the success rate for attempts to start pregnancies.
Currently, only around 34 per cent of IVF cycles in the US result in pregnancy. By selecting embryos on the basis of their metabolic profile, Seli's team increased the pregnancy rate to more than 80 per cent in a pilot study, presented at the annual meeting of the American Society for Reproductive Medicine in New Orleans, Louisiana, last week.
Molecular Biometrics, a privately held metabolomics company, presented results of two clinical studies investigating the use of metabolomic profiling to assess embryo viability, a key step in the treatment of infertility by in vitro fertilization (IVF), at the American Society of Reproductive Medicine's 62nd Annual Meeting in New Orleans, LA.
In a podium presentation (O-270) titled Non-Invasive Metabolomic Profiling of Human Embryo Culture Media Correlates with Pregnancy Outcome, Principle investigator Emre Seli M.D., Ph.D. (et. al.) of the Metabolomic Study Group in ART at Yale University School of Medicine reported results of a retrospective multi-center study. The study was designed to assess embryo viability using a novel technology developed by Molecular Biometrics based on the metabolomic profiling of Oxidative Stress (OS) biomarkers. The goal of the technology is to identify metabolomic differences in viable verses non-viable embryos so only the highest quality embryos can be selected for transfer in IVF. This non-invasive test analyzes OS biomarkers in normally discarded culture media. The biomarkers are quantified using Molecular Biometrics' proprietary spectroscopic analysis and advanced bioinformatics.
The study group concluded that detectable differences exist in the metabolomic profiles found in culture media obtained from embryos that cause pregnancy compared to those that do not. The reported metabolomic parameters were established using two different forms of spectroscopic analysis, Raman and Near Infrared (NIR) spectroscopy, with media samples obtained from three different IVF programs. The metabolomic method achieved high sensitivity and specificity of > 85%.
What I'd like to know: Did some of the women produce only embryos that were unhealthy as measured by these methods? If you want to sell your eggs the ability to show a high rate of viable embryos in one egg sale would let you demand a higher price with later customers. This could be a boon to the egg donation market.
Each of the two spectroscopy methods was highly accurate by itself.
In the study, embryo culture medium from 163 embryos from assisted reproductive technology (ART) cycles using fresh donor and nondonor oocytes were evaluated. Normally discarded media from individually cultured embryos was collected at the time of embryo transfer on day 3, and analyzed using both Raman, and Near Infrared Spectroscopy. Metabolomic profiles of OS biomarker concentrations showed distinct differences between culture media of embryos that resulted in pregnancy compared to those that did not. Using a genetic algorithm with Raman analysis, novel OS molecular species were identified and statistically correlated with pregnancy outcome. The compiled outcomes resulted in a specificity of 82% and sensitivity of 95%. Likewise, analysis by NIR resulted in a specificity of 83% and sensitivity of 73%.
Expect a bigger market for assisted reproductive technology (ART) as a result of this advance. Initially it will decrease the demand for donor eggs by increasing the success rate of women trying to get pregnant from their own eggs. However, in the longer run this advance should increase the market demand for both assisted reproductive technology (ART) in general and donor eggs in particular. Why? Because it lowers the total cost of IVF. Success will happen in fewer attempts. Each attempt costs additional money, emotional pain, physical stress, and also costs time that ages a woman's body and makes her less capable of starting and maintaining a pregnancy.
Lower costs, higher assurances of success, and quicker results will entice more women to use IVF with their own eggs and, for some women, with donor eggs. Also, some egg donors will even be able to more quickly build up track records for producing eggs which result in higher percentages of viable embryos and successful pregnancies.
This result may not just increase IVF pregnancy success rates. It might even reduce the problem of birth defects. Some of the embryos that show up as problematic in these tests might be able to start pregnancies but eventually result in problems after birth. The ability to screen out marginal embryos might therefore reduce the incidence of birth defects. Biotechnological advances seem set to make reproduction with IVF preferred over natural sexual reproduction.
Could IVF-PGD one day become the preferred method of conception?
"It is technically possible," says Simon Fishel, a member of the team responsible for the birth of the first IVF baby in 1978, who now runs the Care Fertility group of clinics in the UK. There are, of course, huge obstacles, not least of which is the cost. "You have to pay per cycle," points out Fishel. "You can attempt to conceive naturally over 12 cycles in a year and it costs you nothing."
The "PGD" mentioned above, Pre-implantation Genetic Diagnosis, is the key to why IVF will probably become the preferred way to start pregnancies. Once genetic testing becomes cheap and the meaning of many human genetic variations becomes known IVF with PGD will provide prospective parents with a way to choose genetic variations for their children. That'll provide a way to avoid many genetic defects and to get children who are better looking, smarter, and with more other desired qualities.
Tests that can sort out high quality embryos will lead to the ability to implant only one embryo to start a pregnancy.
Even singleton IVF babies are around twice as likely to be premature or low birthweight. Again, however, multiple embryos could be to blame, because many IVF pregnancies start out as twin pregnancies. When single embryos are transferred, the differences in health vanish (New Scientist, 25 June 2005, p 14). Many countries limit the number of embryos that can be implanted and single embryo transfer could eventually become the norm.
This latest result reduces the costs of assisted reproduction technologies by reducing the number of cycles needed. It also will probably reduce premature births and birth defects. Once coming technologies make it possible to combine that with sophisticated and cheap genetic testing I predict most prospective parents will choose IVF over natural sexual reproduction.
|Share |||Randall Parker, 2006 November 03 05:23 AM Biotech Reproduction|