Immature eggs
9 Replies
pst - April 23

Dear Doctor,
Im in the process of my 4th IVF. Im 32, DH 37. Unexplained Infertility. I had the retrieval on Friday. My docotr wanted to wait an extra day or two but my estradiol levels were getting too high.
24 eggs retreived but 12 were immature. Half were ICSI (5 fertlized) and half inseminated (3 fertilized).
Day 1 - 8 fertilized
Day 2 (today)- Of the 8, 4 are perfect grade 1 and one stopped dividing. Also 4 more fertilized. So as of today, I have 11 embryos. All grade 1's and 2's.
Im guessing the eggs didnt ferttilize on day 1 because they were immature?
Is it likely/unlikely that eggs fertilizing on day 2 will make it to the blast stage?
The embyologist called this morning and said was going to be a day 5 transfer. Does that sound appropriate.
History -During my 3rd cycle 4 embryos made it to the compacted morula stage on day 5. I t was the most optimistic cycle I had. Cycles 1 & 2 were day 3 transfers with below average to poor quality embryos on day 3.
Thank you, pst.


Dr Smith - April 25

A1. Yes, the eggs that fertilized late were borderline mature at the time of the retrieval. As they matured in vitro, they became fertilizable.

A2. Yes, embryos from late fertilization as less likely to make it the blastocyst stage due to inadequate cytoplasmic maturation (the downside of in vitro maturation).

A3. I'm a big believer in Day 5-6 blastocyst stage transfers. Yes, I think its appropriate to wait. Out of the 8 embryos generated from timely fertilization, I would expect about 3-4 to make it to the blastocyst stage. However, if you have polycycstic ovarian syndrome (PCOS), the quality of the blastocyst stage embryos may be compromised. If that is the case, I would anticipate about 2 good quality blastocyst stage embryos for transfer.

Compacted morula is O.K. for Day 5 provided they continued to the blastocyst stage by the morning of Day 6. Bailing out and transferring morula stage embryos on Day 5 does not provide the necessary information about the developmental capacity of the embryos. If it happens again, I would recommend waiting until the morning of Day 6 and identifying the good quality blastocyst stage embryos for transfer/cryo.


pst - April 26

I had my day 5 transfer this morning. I had 4 compacted morulas, all transferred. The RE didnt recommend a day 6 transfer. Two were grade 2 and the other 2 were a little less than grade 2. The embyologist said he wouldnt transfer them if they didnt have a chance. I wasnt too optimistic for this cycle because we had so many immature eggs due to the stimulation protocol. Today, the embryologist said only 6 were mature and the other 6 were borderline mature. The other 12 didnt even have a chance. So out of the six, 4 made it to the compacted morula stage. Last cycle, I had 9 goods embryos on day 3, and 4 made it to the compacted morula. The percentages of the embryos making it to the compacted morula stage on day 5 were higher this that any indication of this being a more hopeful cycle? Is it likely that compacted morulas will make it to the blast stage? Is it normal to have a compacted morula on day 5? If its not a blastocycst on day 5, does that mean its growing too slowly? Thanks.


pst - April 26

FYI - grade 1 is best


Dr Smith - April 27

Most of the embryos that make to the compacted morula stage on Day 5 become blastocyst stage embryos on Day 6. However, they may be of varying quality. It is not unusual for embryos to take until Day 6 to reach the blastocyst stage when the mature/immature ratio is skewed, as in your case. In situations like yours, we always wait until Day 6 to evaluate the blastocyst stage embryos prior to transfer to determine that there is an adequate number of stem cells to generate an ongoing pregnancy. Blastocysts that do not contain an adequate number of stem cells can result in an "empty sac" pregnancy. Close, but no cigar.


pst - April 27

Thanks Dr. Smith. I appreciate your responses. Keeping my fingers crossed. Pst.


pst - April 27

Dr. smith,
If embryos make it to the compacted morula stage on day 5 but do not continue to the blast stage by day there a typical reason why? Is this something that could be possibly corrected with a longer stimulation protocol? Thanks.


Dr Smith - April 28

In my experience, sperm genetics are linked to arrested development at the morula stage. When we perform ICSI with sperm that have poor morphology (no other choice), the incidence of arrest at the morula stage is increased. I don't think its related to the stimulation (but I could be wrong).


pst - April 28

My husbands sperm analysis came back very good each time. Morphology was good. During the last 2 cycles, I had compacted embryos transferred on day 5, so we dont know if they ever reached the blast stage. If we have to do another IVF, I will insist on waiting for a day 6 transfer to make sure they make it to blastocysts. However if they arrest at the compacted morula stage, can genetic testing be done to see if there is a sperm/egg issue? Is there any other type of testingyou would recommend? Thanks.


Dr Smith - May 2

The sperm can be tested for DNA fragmentation. Excessive fragmentation of the sperm DNA can lead to embryonic arrest. The test is called the Sperm Chromatin Structure Assay and is available through

Testing the embryos (PGD) would not lead to a definitive answer as to whether the problem lies with the sperm or the egg.



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