Fertilization rate - what can we attribute it to?

[ocean]

Carole - What are the biggest factors in IVF embryo fertilization rate? Sperm motility (and general health) I expect is part of it. How much is embryologist skill? If you have men with no known sperm issues, and they produce fertilization rates of say 75% and 100%, is that difference in large part the embryologist picking the right sperm and being skilled in ICSI and/or something else?

Thanks!

[Carole]

Carole - What are the biggest factors in IVF embryo fertilization rate? Sperm motility (and general health) I expect is part of it. How much is embryologist skill? If you have men with no known sperm issues, and they produce fertilization rates of say 75% and 100%, is that difference in large part the embryologist picking the right sperm and being skilled in ICSI and/or something else?

Thanks!

Dear Ocean,
The honest truth is that it is amazing to me that IVF works as well as it does. IVF can fail for lots of reasons. There are lab factors: poor culture media, poor technical skill on the part of the embryologist, equipment failure or mis-calibration so that pH and temperature are not optimal. Then there are the physician factors; poor patient stimulation for the female, poor advice for the male regarding sperm collection and abstinence, medications that impair sperm quality, just to name a few. Then there are inherent patient factors in the quality of the egg or the sperm-- like underlying genetic problems that ICSI can't fix.

For ICSI, you need to be able to find a good sperm (depends on male having a good sperm and on technologists skill to pick it up and inject it properly) and also a good egg that can take the DNA from the injected sperm, and do the molecular steps inside the egg to make fertilization actually happen, resulting in a new genetic embryo. So, asking if it's the sperm or the skill of the embryologist that is more important is like asking are the wheels or is the steering well more important for a car to run? Yes, both plus many more parts.

When IVF fails to deliver as expected, it is very hard to diagnose the cause of the failure in most instances- especially if it is patient specific and not happening to multiple patients at once. Because only in the lab do we track a lot of factors- if the problem is outside of the lab, it is almost impossible to troubleshoot. Patient factors are usually not fully understood and even stim drug lot numbers are not routinely identified and tracked so trouble shooting is hard with incomplete data.
I hope this helps. Carole

[nuthinbutpink]

I am not sure if Carole would agree but with all of the factors she describes above, that is why I harp on cycle with a clinic with the best SART stats you can find! If it is a good doctor, a good embryologist, etc. it will show in the stats and if they aren't, well, it shows that too. You are with a great clinic, ocean. They know what they are doing!!

[Luvmyboys]

We had 100% fertilization too! I was surprises because my most of the chromosome abnormalities came from my husband! I would have thought our fertilization rate should have been less than it was considering he had so many abnormals!

[ocean]

Thanks Carole as usual for the detail and deep context - it helps greatly in understanding. In this case, understanding that ivf has a lot of points of rational failure, and it's successes are to be fully appreciated.
And to nbp's point, to focus on picking the highest quality clinic one can.

[Carole]

I am not sure if Carole would agree but with all of the factors she describes above, that is why I harp on cycle with a clinic with the best SART stats you can find! If it is a good doctor, a good embryologist, etc. it will show in the stats and if they aren't, well, it shows that too. You are with a great clinic, ocean. They know what they are doing!!

Nuthininpink,
I absolutely agree that one of the most important things patients can do to increase their odds of success is go to the best clinic in their area- and make sure that the clinic delivers better than average success rates. I have written probably 10 posts on this topic (how to find a good clinic) at my blog. Fertility Lab Insider - Lessons learned from over fifteen years of working inside fertility labs., so yes, I agree whole-heartedly. Good Luck! Carole