Jun 18, 2026 · 6 min · 4 segments
Embryo selection is often viewed as one of the most important factors in IVF success, but is it getting too much credit? In this video, Dr. Sonia Gayete-Lafuente takes a closer look at the science…
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Norbert GleicherHost
David BaradHostAnd today we're going to talk about a topic that may surprise you.
What if embryo selection actually was not as important as we were led to think? And in fact, this is a topic that comes a lot onto the table on the consultations, in the lab, at conferences, even with infertility specialty colleagues.
That's because for decades, IVF research has been heavily focused on trying to find the best embryo that a patient produced in a cohort, assuming that finding that and transferring it first would improve the chances of pregnancy and success of the patient for that given cycle.
And that may feel reasonable, but it actually has been proven to not be necessarily true despite thousands and thousands of publications studying embryo selection.
Because in fact, if you think about it, also non-embryo selection technique will actually make your embryos better.
That is very important to understand because in the best case scenario, deselecting the not so strong embryos to find the one that seems the strongest and transfer first may decrease the time to achieve a pregnancy successfully, but actually may also be damaging or stressing all the embryo cohort by extended embryo culture to blastocyst stage, which is obviously much more challenging than culture to day three.
by freezing, by thawing, sometimes by biopsying, doing repeated cycles, not to talk about the cost of all these techniques and the time that it entails to do all these things.
Most of the times, and I like to use this metaphor because it's very, very clear, if we only let the Marathonians do run the race yes we may we may win the race but also we're not letting anyone else run and then we don't have any backups right or we may have deselected from running the race other athletes that maybe had also opportunities to doing a pretty good job on the race So, yeah, so that's very tricky because this also leads to the fact that by doing all these embryo selection strategies, we may be decreasing the overall cumulative chances of success in a given cycle.
And that matters a lot, especially for low-prognosis patients or couples that have families few numbers of embryos to select from to start with.
So yeah, I hope that this kind of clarified the question of why this is always an ongoing debate.
And I'm not saying that embryo selection is just useless for everyone.
You know, couples with very good prognosis with lots of embryos, with very good ovarian risk there for younger patients that to start with may be interested on trying to decrease this time to pregnancy, understanding the possible attrition that they may be causing in general to the embryos.
And definitely even before you go to the treatment and the planning phase.
So that leads us to the naturally next question, which is why don't we put all our efforts instead of on the post-retrieval strategies to improve a cycle on the actual pre-retrieval strategies and try to make better embryos to start with? Because, of course, the strongest embryos will always come from Stronger ovaries and stronger eggs and better quality eggs overall.
So maybe we should shift our thoughts to understand better physiology of the ovaries, of ovarian aging, of metabolizing.
And also adjust our protocols for ovarian stimulation to the specific needs of a patient.
and do a much better pre-evaluation even before starting any treatment to eventually try to get better embryos to start with instead of trying to select them farther.
And today we're going to talk about a topic that may surprise you.
What if embryo selection actually was not as important as we were led to think? And in fact, this is a topic that comes a lot onto the table on the consultations, in the lab, at conferences, even with infertility specialty colleagues.
That's because for decades, IVF research has been heavily focused on trying to find the best embryo that a patient produced in a cohort, assuming that finding that and transferring it first would improve the chances of pregnancy and success of the patient for that given cycle.
And that may feel reasonable, but it actually has been proven to not be necessarily true despite thousands and thousands of publications studying embryo selection.
Because in fact, if you think about it, also non-embryo selection technique will actually make your embryos better.
That is very important to understand because in the best case scenario, deselecting the not so strong embryos to find the one that seems the strongest and transfer first may decrease the time to achieve a pregnancy successfully, but actually may also be damaging or stressing all the embryo cohort by extended embryo culture to blastocyst stage, which is obviously much more challenging than culture to day three.
by freezing, by thawing, sometimes by biopsying, doing repeated cycles, not to talk about the cost of all these techniques and the time that it entails to do all these things.
Most of the times, and I like to use this metaphor because it's very, very clear, if we only let the Marathonians do run the race yes we may we may win the race but also we're not letting anyone else run and then we don't have any backups right or we may have deselected from running the race other athletes that maybe had also opportunities to doing a pretty good job on the race So, yeah, so that's very tricky because this also leads to the fact that by doing all these embryo selection strategies, we may be decreasing the overall cumulative chances of success in a given cycle.
And that matters a lot, especially for low-prognosis patients or couples that have families few numbers of embryos to select from to start with.
So yeah, I hope that this kind of clarified the question of why this is always an ongoing debate.
And I'm not saying that embryo selection is just useless for everyone.
You know, couples with very good prognosis with lots of embryos, with very good ovarian risk there for younger patients that to start with may be interested on trying to decrease this time to pregnancy, understanding the possible attrition that they may be causing in general to the embryos.
And definitely even before you go to the treatment and the planning phase.
So that leads us to the naturally next question, which is why don't we put all our efforts instead of on the post-retrieval strategies to improve a cycle on the actual pre-retrieval strategies and try to make better embryos to start with? Because, of course, the strongest embryos will always come from Stronger ovaries and stronger eggs and better quality eggs overall.
So maybe we should shift our thoughts to understand better physiology of the ovaries, of ovarian aging, of metabolizing.
And also adjust our protocols for ovarian stimulation to the specific needs of a patient.
and do a much better pre-evaluation even before starting any treatment to eventually try to get better embryos to start with instead of trying to select them farther.
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3 of 3
Embryo Selection Overrated
She questions everything about standard embryo selection.
Fix Eggs, Not Embryos
She urges improving eggs before lab work.
Marathon Runners Metaphor
Her marathon analogy changes IVF success perspectives.
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