The day of your embryo transfer can shape everything that follows — but for some patients, the bigger fear is whether there will be a transfer at all.
Has this ever happened to you? Your entire IVF cycle felt “wasted” because you made only a few embryos that didn’t survive in the laboratory to become blastocysts (day 5 embryos), so you did not have an embryo transfer at all? It’s a question all IVF patients deserve a straightforward answer to: which day actually gives your embryos the best shot?
With all seriousness, if no embryo(s) are transferred into a uterus in a fresh IVF/ICSI cycle, there can be no pregnancy — excluding embryos biopsied for genetic testing with a plan for future thaw and transfer of a normal embryo. This refers specifically to IVF/ICSI cycles with no plan for genetic testing that intend to proceed with a fresh embryo transfer.
Historically, decades ago, almost all fresh embryos were transferred on day 3, not day 5, since laboratory capability could not grow embryos in culture to blastocyst at that time. Currently, most IVF labs include CCRM’s IVF lab can culture embryos to blastocyst for fresh transfer or biopsy for genetic testing.
Why Day 5 (blastocyst) culture helps (and Why It Doesn’t Always)
The advantage of a day 5 or blastocyst transfer is a higher implantation and pregnancy rate per embryo transferred, since weaker embryos will not survive that long in culture — the embryologists are essentially’ stressing’ all of the embryos to detect the best-quality ones, while also decreasing the chance of multiples by transferring fewer embryos overall. This method is most helpful for women and couples with so many embryos to choose from that embryologists can’t estimate which are strongest on day 3, so they observe their development for a few more days instead.
It’s important to understand what this method does not do: it does not improve the chance of pregnancy from any individual embryo identifies the strongest ones among a larger group that survive. As we all know, there is great biologic variability in women’s cycle response to quantity and quality of embryo number and development. If a patient only has 2 or 3 embryos, prolonged culture doesn’t improve their quality, and the best chance for pregnancy is an earlier transfer on day 3. In women with few embryos in the lab, it is often better to do a day 3 transfer rather than “push” these few or sub-optimal embryos to day 5 for a blast transfer — these embryos may “arrest,” and then there is no transfer at all on day 5.
A word on “meant to be”
Some IVF patients have been told that normal embryos will develop to blastocysts in the lab, and if all of their embryos died, it was “meant to be” — implying their embryos were abnormal and they either would not conceive at all or would miscarry an abnormal fetus. There is absolutely no scientific evidence for these opinions.
Hundreds of thousands of children have been born after the transfer of day 3 embryos, and this is also true for patients today. With all respect to our embryology colleagues, a woman’s uterus is still a better “incubator” than a laboratory — many day 3 embryos can thrive and implant in a woman’s uterus for a pregnancy that simply cannot survive in a laboratory environment.
At CCRM Fertility, we perform both day 3 and day 5 embryo transfers. Our recommendations are individualized for each patient rather than a “one size fits all” approach, as we work to achieve the highest chance of a healthy, term live birth.
Talk to your care team before day 5
Each IVF patient should have the discussion with their doctor about the transfer philosophy long before a possible “sad phone call” on day 5 that their transfer is cancelled due to the arrest of all of their embryos. If you have already gone through an IVF/ICSI cycle and received that call — that all of your embryos have “arrested” and you will not have a transfer — seek a second opinion before your next cycle. You could become pregnant with an embryo transfer on day 3.
For more information or to book an appointment, contact us online or schedule an appointment with CCRM Fertility.
