A Research Study conducted by the Colorado Center for Reproductive Medicine evaluated the efficacy of a single embryo transfer in IVF patients up to age 42, utilizing day 5 embryos (blastocysts) that had comprehensive chromosomal screening, to determine that they were chromosomally normal (euploid).
While the women of advanced maternal age (38 to 42) had a blastocyst aneuploidy rate of 62.4%, as compared to 36.7% in women 37 or younger, following a frozen transfer of a single euploid blastocyst embryo, live birth rates were almost identical in both age groups: 60 percent in women of advance maternal age; 64.6 percent in women 37 or younger.
The study analyzed 1,000 infertility patients who had a single, chromosomally normal frozen blastocyst transfer with their IVF cycle. All the embyros were biopsied on Day 5, the blastyocyst stage, for comprehensive chromosomal screening (CCS).
“What the study says is that if you correct for aneuploidy, if you screen out embryos that are chromosomally abnormal, and you’re transferring a single embryo, the success really has no variance with age up to and including age 42,” says Dr. William Schoolcraft, founder and medical director of the Colorado Center for Reproductive Medicine.
“If you look at SART and CDC data nationally, what you see if the opposite. There’s a profound decline in success rates around age 35 and it’s linear. What we’re saying is ‘yes, that’s true, because obviously your putting back more genetically lethal embryos as the patient is getting older’. But if you take these same patients and you screen out the abnormal embryos [with CCS] and you’re putting back a normal embryo, then up to 42, age has no impact,” Schoolcraft adds.
With CCS, a few cells from a blastocyst are biopsied and the embryos are frozen. Only embryos that are determined to have the correct number of chromosomes are transferred in a frozen embryo transfer.
“I’ve been taught and I tell my patients – or at least I have for the last 20 years – that age is everything,” Schoolcraft says. “It’s a big if, but if you can get a chromosomally normal embryo suddenly that decline goes away. That to me has been the most remarkable thing about CCS. Because that’s not the dogma that we’ve all believed.”
The study involved women up to age 42, because at the age of 43 there is a drop in success even with chromosomally normal embryos, Schoolcraft says, due to underlying issues with the eggs’ mitochondria and metabolics.