“Dear Sensible Surrogacy.
After a long wait, we finally had our embryo transfer performed this week — we are crossing our fingers and praying for a positive HCG test. Everything went fine, but we were told by the clinic that the thawed embryo was “collapsed” and so the embryologist was not able to evaluate its quality. This sounds terrible! Will a collapsed embryo lower our chance of a pregnancy? –Scott and Jason
Good morning Scott & Jason,
First let me say that we are all crossing our fingers for your positive pregnancy test next week! We love a happy ending, regardless of who is the clinic or the embryologist. So we’ll be joining your prayers!
A quick word about the very dramatic term “collapsed” blastocyst…
“Collapsed Blastocyst” (or Collapsed Embryo) is certainly an unfortunate term that can drive fear into Parents, but it’s really not as terrible as it sounds.
Blastocysts in-vitro typically undergo repeated collapse and expansion before they arrive at the point where they are ready to “attach” and latch onto the uterus wall. This is a normal part of the embryo’s growth cycle. In a typical IVF cycle, the cycle of collapse and expansion is actually a sign that the embryo is developing correctly. The phenomenon has also been called blastocyst “breathing”. There’s a full discussion about embryo development in the Surrogacy Guide.
Embryo development is a dynamic process, and the embryo characteristics will repeatedly change significantly over a time span of only a few hours. The typical Gardner grading scale (3AA, 4BC, etc…) is made with a limited number of observations. But between those observations the embryo isn’t just sitting there doing nothing… The embryo goes though many changes and it’s appearance changes dramatically.
Before an embryo moves from one developmental stage to another (from one cleavage to another) it often goes through a collapsed state. This happens when the fluid in the cavity is released, triggering the next stage of development. It can take about 5 minutes for an embryo to collapse, and then it re-hydrates over the course of the next several hours. So if your embryos are approaching a developmental milestone, it’s not unusual that you may catch them at a collapsed point. It’s also not unusual for the freezing process to trigger a collapse, and so re-hydration is a first step in the thawing process. Re-hyrdation can happen in the IVF lab, or in the uterus.
I hope this is useful.
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