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PGD and Frozen Embryo Transfer: The New Standard for IVF?
PGD and Frozen Embryo Transfer: The New Standard for IVF? Interview with Jamie Grifo
Some of the latest research in the field of reproductive medicine focuses on ways fertility doctors can transfer fewer embryos with higher pregnancy rates. Frozen embryo transfers (FET) yield greater pregnancy rates than fresh embryos due to improved uterine receptivity, and preimplantation genetic diagnosis (PGD) is indicated as another method for improving success and safety with a single embryo transfer (SET).
Jamie Grifo, M.D., Ph.D., of NYU Fertility Center, says his Single Thawed Euploid Embryo Transfer (STEET) study sought to provide in vitro fertilization (IVF) patients with one healthy child while reducing the incidence of pregnancy loss and costs associated with a multiples’ pregnancy. This study and others across the country, including the research of Bruce Shapiro, M.D. in Las Vegas which examined the efficacy of frozen embryos in IVF, point to an almost obvious solution: utilizing genetic screening and thawed embryos for maximizing success and minimizing risk.
“The problems with IVF are pretty well known: pregnancy rates are not as good as they should be (on average, 42% in those under 35), the miscarriage rate is too high, ectopic pregnancies account for two percent of IVF pregnancies, and the risk of overstimulation is too high. Multiple gestations are the biggest problem. We’ve tolerated these issues [in the past] because it was the best we could do, but now it is not the best we can do,” Grifo says the technology exists to improve IVF outcomes.
Allowing the endometrial lining to recover from the harsh effects of fertility drugs increases uterine receptivity for a frozen embryo to implant. PGD, in particular array CGH, has the ability to examine all 23 pairs of chromosomes for genetic abnormalities. These two techniques combined have the ability to produce success rates comparable to those of a healthy, young, donor egg cycle. “We’ve done this on patients with multiple failed IVF cycles and multiple miscarriages. These are patients with a relatively poor prognosis, yet 55% of the embryos make a viable pregnancy- rates that are unique to an egg donor cycle or young patients without uterine factors,” he says. Women over the age of 40 produce embryos that are 90% genetically abnormal, while women in their 30s produce 50-60% genetically abnormal embryos. CGH screening would allow embryologists to select genetically normal embryos to be transferred in a subsequent cycle when the uterus reaches prime receptivity.
The risk of PGD on blastocysts is nearly immeasurable, with a 99% survival rate after biopsy and thaw. “[The reasons for doing STEET are] very clear if you’re a data person,” he advises.
Aside from the high implantation rates, high rate of singleton pregnancies, and ability to eliminate the effects of age on a pregnancy by selecting the most chromosomally sound embryos, the strongest argument for moving toward STEET is the decreased miscarriage rates. Grifo states: “The most remarkable piece of this is that you’re preventing miscarriage, D and C (Dilation and Curettage), heartache, and disappointment. That alone is the justification to do this, to lower the miscarriage rate.”
Moreover, the STEET study has not seen any ectopic pregnancies or ovarian hyperstimulation and has significantly reduced the physical and financial costs associated with multiples’ pregnancy, birth, and time spent in the neonatal intensive care unit (NICU). Dr. Grifo believes that especially from an insurance or cost standpoint - to be able to dramatically reduce costs and risks by transferring single embryos-, it is going to be hard not to justify SET going forward.