Stem cells for continued pregnancies
2 Replies
brenda - November 24

Hi Dr. Smith
I want to thank you again for your support and your wisdom and knowledge, you have qualmed and answered so many questions I have as well as other ladies on this board. i trust this website very much.

In a prior post, you made mention of stem cells of the embryos are necessary for continued growth in the uterus. Where are the stem cells located, what are the parts of the embryo, there is the trachoblast, sp, but what is the middle part of the embryo called and is this where the stem cells live.

also would an infection during the 2 week wait interfer with the attachment, and implanting of the embryos?

My white blood counts were elevated during the 2 week wait

I was wondering if this had anything to do with it. Also the embryos were only developed to day 2, and then transfered.
do you think transferring the embryo on day 2 lessened the embryos chances of surviving in the uterus? the embryos were at 6 cell and b+ grade.

Also if the embryos were given the correct amount of time to go to day 3, could the embryos grade improved over day 2 development or just stayed the same?

We still have some embryos left over from that cycle and hopeful that it will work on the remaining frozen.

I am concerned bc my husband morphology was 5 on a strict scale and not sure what his dfi was at that time.

if there is a sperm dfi problem when will the miscarriage happen in the first trimester, will it happen more likely in the first few weeks after implantation?


Dr Smith - November 25

When the embryo develops to the blastocyst stage, it is composed of roughly 60 cells. The cells are arranged in a hollow, fluid-fill ball (hence the term "cyst" in blastocyst). The cells that form the "skin" of the ball are called the trophectoderm and will form the sac the embryo grows in. Inside the ball, attached to the inside surface of the trophectoderm are about a dozen stem cells. The appear as a thickening on one side of the inner surface of the blastocyst and are referred to as the "inner cell mass". The stem cells will give rise to all fetal tissues during development (stem cells = baby). There must be an adequate number of stem cells (i.e. the inner cells mass must appear big enough) in the blastocyst stage embryo for continued development. If there are too few stem cells, the embryo will stop growing shortly after implantation (i.e. in the first month) and will be lost as a chemical pregnancy or "empty sac" miscarriage. This is a fairly common occurance in humans.

An infection of the endometrium (endometritius) could certainly interfere with implantation. It is less clear if a systemic infection would cause a problem. Since I'm not a physician, perhaps you should ask Dr Jacob on the Infertility 101 Message Board.

If the embryos were hearty, transferring them on Day 2 would not cause them any problems. They must, however, have the correct genetic instructions for continued development and that is impossible to determine on Day 2.

Rarely, but it does happen, an embryo's grade can improve between the Day 2 assessment and the Day 3 assessment. Usually it will stay the same or get worse.

The negative impact of a high amount of DNA fragmentation (DFI >30) occurs during the first trimester. Exactly when (i.e. first few weeks?) is hard to tell, but off hand I'd say that it more likely to impact embryo development in the first few weeks rather than late in the trimester. I don't have any facts to back me up there, I'm just winging it.


brenda blankenship - November 29

Thank you Dr. Smith, I am preparing my questions for Yale and it is good to go with some information and this is good information.
I have tons of questions and I am sure they will too. I have seen them in the past and totally respected their opinion of me before, and was treated with dignity and respect.
You are wonderful. i have a friend who is a lab director for a cryo bank but not a ivf lab, he knows sperm but not embryology.
thanks again for the wonderful support you have been to me and my husband. I sincerely appreciate it and your explanations are top notch.
we do appreciate it.



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