What Having a 'Perfect' Embryo Actually Means
The most confusing, terrifying thing after an egg retrieval, is patiently waiting for the embryologist to call with those daily embryo lab report updates. I was always left waiting and wondering, how many embryos fertilized, and how many embryos are continuing to grow. Then, on the final day, how many embryos did we end up with? So many questions surround embryos, and we often get asked, “what do all the grades mean?” and “what is a perfect embryo?”
The IVF Warrior: Day 5 Hatching Blastocyst
What Having a 'Perfect' Embryo Actually Means
According to Embryologist, Kristen Jones, statistically, the higher graded embryos such as a hatching or expanded AA on day 5 have the best success rates. For cleavage stage embryos, studies show embryos that are 4 cell on day 2 and 8 cell on day 3 have a greater chance of success, as do embryos which show signs of early compaction (day 3, as we normally see compaction on day 4). Meaning, 4AA or 5AA embryos are considered “perfect.”
After having a recent transfer, I was curious about the complete breakdown of what it actually means to transfer a top quality “perfect embryo”, the embryo that we all desperately strive for. First, let’s take a look at the blastocyst stages image below, displaying day 1 through 5:
Based on this chart, it's clear which embryos are considered 'poor', 'average' and 'good.' Notice that this chart hasn't included embryos with a day 5/6 grading. When a blastocyst scores a 5AA grade, it means it’s starting to “hatch” with normal appearing inner cell mass and trophectoderm. Therefore, when a blastocyst scores a 6AA on day 5, the blastocyst is completely “hatched” with nice inner cell mass and trophectoderm.
What does it mean to transfer a top quality “perfect” embryo then?
Typically, the lab allows embryos to grow for 3 or 5 days. If you are considered the lucky few who get a 4AA or 5AA embryo, the pregnancy success rate is considered to be 63-65% for a single transfer. These embryos implant as well as PGS tested embryos (genetically tested). What surprised me the most about high-quality embryos were actually the gender stats. Did you know that you have a 72% chance of a top-quality embryo being male? That means you only have a 28% chance for a female. Male embryos develop quicker in the early stages, which is why there's such a drastic difference between the two. Gender selection is nearly impossible at this stage then. I personally managed to get a girl (4AA) and a boy (5AA), so anything is possible!
With all of this information, it's not surprising that we all want an army of top-quality embryos! Unfortunately, there are so many things in our environment, diet and modern way of life that can affect fertility. Luckily, there are some easy ways to boost fertility that can increase your chances of getting pregnant, and most of them involve simple lifestyle changes that you can start today. A lot of people start taking high-quality supplements and make lifestyle changes at least 3 months before a fresh IVF cycle to try to increase egg and sperm quality.
Embryologist, Kristen also shared a reminder that though statistically, better graded embryos do have a higher implantation rate and higher clinical pregnancy rate, you can’t do anything about the embryos that you have, so don’t stress too much as you can’t do anything about it. Poor quality embryos can make healthy babies, and the most beautiful embryos can fail. Of course, we like to see transfer of good quality embryos, however the reality is, it's not always possible and that doesn’t mean the chance of pregnancy is impossible.
Want to learn more about embryology from an Embryologist? Click here for more articles.
Medical Disclaimer:
The information provided in this blog is intended for general informational purposes only and should not be considered as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your healthcare provider or qualified medical professional with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read in this blog.
