Advances May Improve Success Rate for In-Vitro Fertilization
October 13, 2014
Two New Techniques Aim to Make It More Likely That a Single Embryo Will Lead to a Pregnancy
by Lisa Ward
New techniques offer the possibility of improving a patient's odds of having a baby through in-vitro fertilization. A single IVF cycle has about a 32% chance of resulting in a live birth, according to statistics from the Centers for Disease Control and Prevention. To improve the odds, doctors often implant multiple embryos in the uterus during a single IVF cycle, leading to a high rate of twins and triplets. Multiple births can lead to serious health complications for mother and child and significantly increase health-care costs, says Emre Seli, director of the Yale School of Medicine's division of reproductive endocrinology and infertility.
Two new techniques aim to improve the likelihood that implanting a single embryo will allow a patient to have a baby.
A. Screening Chromosomes
The technique furthest along, and already used in select clinics around the world, is called preimplantation genetic screening. In this procedure, cells are removed from the embryo on day five (or day six) to see if the normal amount of genetic material is present. An embryo should have 23 pairs of chromosomes; those with extra chromosomes or missing chromosomes are considered less viable.
"Chromosome abnormality is the main cause of miscarriage," says Richard Scott, clinical and scientific director at Reproductive Medicine Associates of New Jersey, a fertility clinic and the reproductive endocrinology and infertility division of Rutgers University's Robert Wood Johnson Medical School.
(The process is different from searching for a specific disease or genetic disorder that is likely to manifest later in life, which is known as a preimplantation genetic diagnosis.)
Chromosomal screening has shown promise in three small, randomized studies. A study co-authored by Dr. Scott, for instance, found that transferring a single embryo after chromosomal screening resulted in a similar rate of live births as transferring two untested embryos.
Still, some experts say more research is needed.
"A major study with an adequate number of patients is needed to definitively determine the degree of benefit," says Christos Coutifaris, chief of reproductive endocrinology at the Perelman School of Medicine at the University of Pennsylvania, adding that this is especially true given the price tag. The procedure costs about $4,000—a hefty fee on top of an already expensive process that often is paid for out-of-pocket. The average IVF cycle costs about $12,400, according to the Society for Assisted Reproductive Technology.
B. Monitoring Cell Division
Time-lapse imaging, which costs about $1,500, is a less invasive method of evaluating embryos. It's already used in clinics around the world, but new types of time-lapse screening are just becoming available commercially. With time-lapse imaging, thousands of pictures are taken to record a fertilized egg cell dividing. Eggs dividing atypically are unlikely to survive.
"The embryo's fate can be determined very early in development," says Barry Behr, director of Stanford University Medical Center's IVF laboratory.
Dr. Behr co-wrote a study identifying three markers that determine if a four-cell embryo (on day two) is likely to reach blastocyst, a critical stage where it has divided into about 120 cells (on day five) and has a better chance of implanting in the uterus. The study created an algorithm to do the analysis automatically.
Auxogyn Inc., based in Menlo Park, Calif., and Unisense FertiliTech AS, based in Copenhagen, make devices that use time-lapse imaging. Both companies are coming to market with products that use algorithms to automate the evaluation process. Currently most clinicians analyze time-lapse imaging subjectively.
Time-lapse imaging may also work in tandem with chromosomal screening, since it provides information about an embryo's metabolisms unavailable through genetic testing. An initial study was promising.
The technique furthest along, and already used in select clinics around the world, is called preimplantation genetic screening. In this procedure, cells are removed from the embryo on day five (or day six) to see if the normal amount of genetic material is present. An embryo should have 23 pairs of chromosomes; those with extra chromosomes or missing chromosomes are considered less viable.
"Chromosome abnormality is the main cause of miscarriage," says Richard Scott, clinical and scientific director at Reproductive Medicine Associates of New Jersey, a fertility clinic and the reproductive endocrinology and infertility division of Rutgers University's Robert Wood Johnson Medical School.
(The process is different from searching for a specific disease or genetic disorder that is likely to manifest later in life, which is known as a preimplantation genetic diagnosis.)
Chromosomal screening has shown promise in three small, randomized studies. A study co-authored by Dr. Scott, for instance, found that transferring a single embryo after chromosomal screening resulted in a similar rate of live births as transferring two untested embryos.
Still, some experts say more research is needed.
"A major study with an adequate number of patients is needed to definitively determine the degree of benefit," says Christos Coutifaris, chief of reproductive endocrinology at the Perelman School of Medicine at the University of Pennsylvania, adding that this is especially true given the price tag. The procedure costs about $4,000—a hefty fee on top of an already expensive process that often is paid for out-of-pocket. The average IVF cycle costs about $12,400, according to the Society for Assisted Reproductive Technology.
Time-lapse imaging, which costs about $1,500, is a less invasive method of evaluating embryos. It's already used in clinics around the world, but new types of time-lapse screening are just becoming available commercially. With time-lapse imaging, thousands of pictures are taken to record a fertilized egg cell dividing. Eggs dividing atypically are unlikely to survive.
"The embryo's fate can be determined very early in development," says Barry Behr, director of Stanford University Medical Center's IVF laboratory.
Dr. Behr co-wrote a study identifying three markers that determine if a four-cell embryo (on day two) is likely to reach blastocyst, a critical stage where it has divided into about 120 cells (on day five) and has a better chance of implanting in the uterus. The study created an algorithm to do the analysis automatically.
Auxogyn Inc., based in Menlo Park, Calif., and Unisense FertiliTech AS, based in Copenhagen, make devices that use time-lapse imaging. Both companies are coming to market with products that use algorithms to automate the evaluation process. Currently most clinicians analyze time-lapse imaging subjectively.
Time-lapse imaging may also work in tandem with chromosomal screening, since it provides information about an embryo's metabolisms unavailable through genetic testing. An initial study was promising.
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