Did I make enough blasts?

A lot of new patients who go through IVF are disappointed around embryo transfer day when they're told the number of useable embryos they have.

The majority of couples hope to see most of their embryos reach the blastocyst stage and that's not always the case.

Unfortunately in the field of fertility, humans are not very efficient at making high quantities of good quality, useable embryos. We were not designed to.

Even during IVF when we exaggerate the number of eggs produced per cycle using hormones, we still achieve around a 50% blast rate for patients under 35 yrs old. 35-39 yr olds see around 20-40% mature to blast, and for patients over 40, we see sometimes just 1 or 2 blastocysts total.

As women age, egg quantities and quality declines, and so too does the number of blastocysts. We have heard this a million times. But if you look at this constructively, what we can do is isolate the better performing embryos from the cohort.



For example, in the photo above, all of these embryos looked almost identical on Day 3, but on Day 5 we saw 3 blasts and 3 arrested embryos. So we went from 6 out of 6, to 3 out of 6. The advantage of doing Blast culture helps us to separate the strong from the slow and ultimately that will translate to better pregnancy rates.

Don’t be discouraged even if you only make 1 or 2 blasts. This is still a great result. As humans, we are designed to come from 1 egg ovulating to make 1 blastocyst.