Day 5 embryos are at the blastocyst stage, when embryos have developed to the point when they are typically transferred. Day 5 of embryo development in IVF is pivotal as it signifies advanced development, allows for precise quality grading, supports selective embryo transfer and increases the chances of achieving a successful surrogate pregnancy.
Transferring blastocysts on day 5 or 6 of development leads to higher implantation rates compared to embryos transferred at earlier stages.
Contact us online to learn more about the specific steps you can take for surrogacy at the time of your embryo’s development. Not only can we walk you through the importance of day 5 embryos and what they mean for your journey, we can help you with everything needed to get to this point.
That could entail connecting you with reputable fertility clinics where you can choose to create your embryos or using our decades of experience creating families to help you find a surrogate in an average of just 1-6 months.
Day 5 Embryo Development [The Blastocyst]
By day 5, the compacting embryo is beginning to take shape in the form of a blastocyst.
A blastocyst is a cluster of dividing cells that happen as a result of fertilization, it’s also one of the many steps that lead to a pregnancy.
As the blastocyst continues to divide and separate, it forms a fluid-filled cavity called the blastocoel along with two other collections of cells.
One is called the inner cell mass (ICM), which eventually becomes the fetus, and the other collection of cells is called the trophectoderm that forms the placenta.
Is A Day 5 Embryo Good?
Yes, a day 5 embryo is good. Day 5 embryos allow more time for the embryos to grow, leading to embryos that are selected with a higher chance of success.
Fewer embryos will need to be transferred because they have a higher chance of implantation than day 3 embryos.
What Makes A Good Quality 5 Day Embryo Blastocyst?
The quality of the day 5 embryo can be broken down into three parts.
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Expansion of the cell cavity: Graded using numbers 1-6
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Appearance of ICM: Graded using letters A-C
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Appearance of the trophectoderm: Graded using letters A-C
Here’s an example of what a day 5 embryo grade may look like: 5AA
The number correlates with the “grade” given to the expansion of the cell cavity with one signifying the cavity is less than half the volume of the embryo and six means the trophectoderm has burst through the shell surrounding the embryo. The first letter in this scenario denote the grade of the ICM, where the letter A means a cohesive layer of many cells and C means few large cells. The second letter grades the trophectoderm with the letter A meaning there are many tightly packed cells and C meaning there are few cells.What Those Letters and Numbers Mean
There isn’t an exact science to the blastocyst grading scale as it depends on the fertility center and doctor you work with, but the end result of this grading system determines what blastocysts have the highest chance of success.
What Are the Day 5 IVF Embryo Transfer Success Rates?
Further developed blastocysts have a higher implantation rate because of their maturity vs. day three embryos.
The extra two days come closer to mimicking natural implantation after sexual intercourse and allow for more development and a higher chance of normality with the chromosomes.
Those extra days in the incubator result in you needing to transfer fewer blastocysts for the chance of a pregnancy to take, keeping success rates high.
While success rates can vary, depending on individual circumstances and clinic-specific protocols, here are some general success rate ranges for day 5 embryo transfers:
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Implantation Rate: Typically around 50% per embryo transferred compared to 30% of day-3 transfers.
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Clinical Pregnancy Rate: Generally around 70% per embryo transfer compared to 66% of day-3 transfers.