First, let me make it clear that embryo grading doesn’t look at genetics. If you want to know more about pre-implantation genetic screening (PGS), visit www.chromosome-screening.org.
Embryo grading means we look at embryos under a microscope and estimate whether they have the potential to continue to grow into a healthy, ongoing pregnancy. Grading is done by removing embryos from the incubator for a few seconds (up to a minute) every day, or nearly every day, for the first three to five days prior to embryo transfer. This gives us about two minutes worth of data acquisition over the ninety-six hours it could take to grow an embryo into a blastocyst.
But it’s an inexact science at best. The embryos are only a few days old. There’s a lot of development that happens over nine months.
Recently, we have been using cameras that follow embryo development 24/7. It sounds better, and in some ways it is. It’s an extraordinary amount of information to have. One of the current challenges is what to do with it all.
All kinds of patterns have been observed, but their clinical significance, at this time, remains unclear. If an embryo is not growing as well as expected, does that mean it should never be transferred? Often, we don’t know.
In the months ahead, I’ll be able to share more information with you as we collect more data.