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Thread: Collapsed blastocysts

  1. #1

    Default Collapsed blastocysts

    I had a collapsed blastocyst transfered a few days ago - I will freely admit that having my embryo described as collapsed did absolutely nothing to inspire my confidence, despite my FS saying "it's what blastocysts do, they collapse and expand". Never much opportunity to ask questions during transfer (especially not when the FS is over an hour late and there's a new embryologist being shown the ropes!), so I researched... and I thought I would share it here for others...

    Blastocysts in vitro typically undergo repeated collapse and expansion before they escape from the zona pellucida. Collapse is rapid, occurring in less than five minutes whereas complete re-expansion requires several hours. The phenomenon has been called blastocyst ?breathing? and occurs just before hatching. It is not known whether or not it occurs in vivo .
    Hatching is the process by which the expanded blastocyst breaks through and escapes from the zona pellucida. It must occur before implantation into the endometrium is possible. Hatching of healthy blastocysts in vitro usually occurs between post insemination days 7 and 8.

    Hatching begins with the gradual accumulation of fluid in the blastocystic cavity and expansion of the blastocyst. The fluid accumulation causes increased pressure on both the trophoblast and the zona pellucida. Simultaneously, trophoblast cells proliferate to form a cohesive, single layer. The blastocyst contracts and expands intermittently. Proper expansion of the blastocyst by intake of fluid into the blastocystic cavity causes an increase in internal hydrostatic pressure that stretches the trophoblast epithelium. The blastocyst enlarges and its volume increases two- to three-fold causing the zona pellucida to thin. The blastocyst usually hatches out at the pole opposite the inner cell mass. The hatching locus is indicated by the appearance of a group of large, rounded, plump trophoblast cells called zona-breaker cells.

    Usually the trophoblast cells begin to herniate through the zona pellucida first just prior to hatching. Once an opening occurs, the blastocyst begins to protrude through. After about 50% of the blastocyst has hatched out, the remaining process is completed quickly. After the zona pellucida ruptures the eventual size of the opening produced is about one-quarter to one-third of the circumference of the capsule so that blastocyst escape is easy and rapid. During hatching and immediately afterwards, collapse and expansion of the blastocyst is a common phenomenon.
    The way I read this... blastocysts collapse and expand several times before they eventually hatch and implant. While having a collapsed blastocyst sounds dreadful, it's a good thing. It means that it has survived the thaw (in my case at least) and is growing and progressing and getting ready to implant.

    I was immensely relieved after I found this out, and much happier about the state of my little embryo! Hopefully this information is helpful to someone else, too.


  2. #2

    Join Date
    Mar 2007
    on cloud 9.....


    BW, you had me worried when I read the title of your post cause as you said, it doesn't sound too good. What an interesting read, I must say. Best of luck and I pray to hear some good news from you soon. xx

  3. #3

    Join Date
    Dec 2006
    In my own private paradise


    interesting info BW - it's amazing the bits we DON'T get told - and have to go home to stress about isn't it?!?!?

  4. #4
    *Nessa* Guest


    Wow BW, that was interesting.

    BTW good luck, i have fingers crossed for you!!!!

  5. #5


    Thanks everyone. Some days I'm simply astounded by the amount of stuff that you learn going through assisted conception. Although, I'm glad I never became a doctor! It's hard enough to get my head around the things that I need to deal with - I don't think I've got the brain capacity for what a doctor needs to know!

    And I'm awfully relieved that I wasn't the only one to have that reaction to the term "collapsed blastocysts"! It sounds dreadful, but it's actually a good thing!


  6. #6

    Join Date
    Jul 2006
    In The Land Of Wonderful...


    This Is Good News!!

    We had the same thing happen to us last time - They transferred 2 hatching blastocysts, and when my FS was transferring them back he said we needed to get it done before they collapsed.... (He was joking, but I didn't get it!) At the time I was COMPLETELY stressing out thinking OMG What does that mean???!!! (Thinking they were going to collapse and die before they got in there!!! ).... I couldn't figure out that despite saying that to me, he then proceeded to take his time with the transfer - It was only after he explained, that both DH and I lost our looks of horror on our faces!!!

    Its just great when they do things like that to you
    Like the whole thing isn't stress enough in itself....

  7. #7

    Join Date
    Oct 2006
    Country NSW


    Hi BW,
    That great news. Its so great having all you wonderful woman sharing your experiences so this way none of us will freak out when we or if we get told the same thing. I am about to undergo a FET by end of Feb beginning of Mar so i'm glad i've just been a little more educated. Thankyou for sharing.
    Wishing you so much luck with this one - hope we see BFP announcement from you soon. Are you going to to a HPT or wait for the BT? Tell me if i'm being to nosy. I have been watching you over the years and so hope this is it for you BW. and to you.

  8. #8


    Thanks, Lissie, you're very sweet for keeping such an eye on me. I want to wish you the best of luck with your FET coming up. I like FETs, they are simple and fuss-free (but then I get to do natural ones!)... and I've never had a fresh transfer, so I guess I'm biased!

    I'm pretty sure I won't be giving in to the lure of the evil pee sticks! After being through two transfers with strong pregnancy symptoms (even though one was a chemical pregnancy), I'm actually quite confident that I can trust what my body is telling me. It seems rather pointless to resort to HPTs, when I know without a shadow of a doubt what's going on in my body now... add to that the inability to get a positive on a pee stick before my positive blood test first time around, and I'm actually quite content to wait and see. My clinic tests quite early, which certainly helps!


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