You are here
Embryo Banking for Patients with Diminished Ovarian Reserve and Previous IVF Failure
A recently published study demonstrated that banking zygotes (one-cell, fertilized embryos) for comprehensive chromosomal screening (CCS) helps achieve ongoing clinical pregnancy in women with diminished ovarian reserve who have had previous IVF failure.
Patients with diminished ovarian reserve (DOR) often don’t produce enough blastocysts for CCS, a type of preimplantation genetic screening to evaluate of all 23 pairs of chromosomes. And women of advanced maternal age have an increased chance of producing abnormal embryos. This study looked to increase the number of blastocysts available for CCS in patients with diminished ovarian reserve.
Researchers from Colorado Center for Reproductive Medicine (CCRM) took part in the observational crossover study. According to Dr. William Schoolcraft, Founder and Medical Director of CCRM, women who are poor responders may only make three, four or five eggs in one IVF cycle, with only one or two eggs fertilizing at time, then grown to the blastocyst stage and tested with CCS. “The patient is going to go through a lot of cost each time if it takes three [IVF] cycles to get one or two good embryos,” he says
“So the thought was to let them do three retrievals then grow all of the one-cell, fertilized embryos together to blastocyst on the third cycle, and do the CCS once on all the embryos.”
On cycle one, the eggs were retrieved, fertilized and frozen at the one-cell stage. The one-cell zygotes are almost impervious to freezing, according to Schoolcraft. On cycle two, it was the same process. On cycle three, the eggs were fertilized at the one-cell stage and the embryos from cycle one and two were thawed and mixed with the embryos from the third cycle. If there were three embryos from each cycle, for example, there would now be nine embryos to test. “Statistically if the patient now has nine, one-cell embryos, she might get five blastocysts and out of five blastocysts she might get two normal embryos. But if she started with just three embryos she might have gotten just one blastocyst and no normal embryos,” Schoolcraft explains.
He adds, “Embryos secrete growth factors that help stimulate development, so it turns out you’re getting the advantage of growing them in larger groups. And then economically the patient pays for blastocyst culture once and CCS once, and she gets more bang for her buck.”
At the time of the study, the ongoing pregnancy rate was 81 percent. The study concluded that compared to conventional IVF, this method of zygote accumulation for CCS, “provides logistical advantages for patients with diminished ovarian reserve over other embryo banking approaches.” But the study also notes that while it, “overcomes the challenges of diminished ovarian reserve by increasing the number of zygotes, maternal age remains a significant hurdle in attaining euploid blastocysts.”