Selecting the best embryo to transfer during IVF
Ovation Fertility Newport Beach IVF center sheds light on selecting the best embryo to transfer during IVF
In the past, embryologists and fertility specialists would grade embryos (A, B and C), just like a report card, based on what they could see and how and when the cells were dividing. A new study conducted by an Ovation Fertility Newport Beach IVF center, debunked two previously accepted truths about selecting embryos.
- Embryos form blastocysts on Day 5 or 6 after IVF fertilization occurs. Some are slower to grow and expand to the point at which they are ready to have cells removed for genetic testing or freezing for later transfer. The study showed an equal proportion of genetically normal embryos regardless of whether they reached the blastocyst stage on Day 5 or Day 6.
- Prior to embryo transfer, the grade of the outside cell layer that will become the placenta (trophectoderm) is more important than the inner cell mass that will form the baby.
“Just because an embryo is slower growing doesn’t mean it’s genetically inferior,” says Dr. Mitch Schiewe, one of the world’s leading reproductive embryologists and high complexity lab director and Ovation Fertility Newport Beach research director. “In addition, our studies confirmed those in Europe showing that embryos with ‘A’ quality outside cells were more likely to implant and sustain the pregnancy, even from a Day 6 blastocyst.”
In 2015, the study was presented at the World Congress of Human Reproductive Medicine in Berlin, Germany and was nominated for a clinical research award at the European Society of Human Reproduction and Embryology in Lisbon, Portugal.
How embryologists determine the best embryo to transfer
“An embryo has to implant, or invade, into the uterus,” explains Dr. Schiewe. “The first priority of an embryo is to have a really robust placenta that can establish a pregnancy first so that it can support the growing fetus later. Then the fetus can catch up even weeks later as cells multiply.”
With genetic testing combined with newer criteria for embryo selection, embryologists now know that looks can be deceiving. The best quality embryos are not necessarily the only “normal” embryos.
What your embryologist wants IVF patients to know about the study findings
Having preimplantation genetic screening or diagnosis prior to IVF transfer clarifies the issue of genetic well-being and which embryo to select, but these new findings benefit all people undergoing IVF, even those who don’t opt for genetic screening.
Better embryos lead to better pregnancy success. What’s more, while twins or triplets may appeal to some couples who long for a child and wish to transfer more embryos to increase their odds, the goal at Ovation Fertility-Newport Beach is a single, healthy baby using elective single embryo transfer, or eSET. Thanks to their study findings, eSET is a viable option to optimize pregnancy outcomes.