Today is a BIG day: we find out if H and I have managed to produce any genetically normal embryos.
After three failed IVF rounds and no embryos in the freezer, we were (naturally) starting to suspect that there might be an egg quality issue. We have tested H’s Sperm numerous times, including performing a DNA fragmentation test, which showed that his sperm contain a whopping 98% normal DNA!! Considering my age, 38, only approx. 30% of my eggs are likely to be normal (the age range of 37-38: 30%-40% of eggs are normal). My AMH is 10.4 (down from 13.2 last year ☹) and shows low-ish fertility for my age, so the odds aren’t great – if 30% of my eggs are normal I’ll take it! This fact sucks, but it’s reality and we have to work with what we have. As an aside, I wish that someone had told the younger me about the reality of rapid declining fertility after 35 (it is NOT a myth)…
So, what is PGS testing?
PGS stands for “preimplantation genetic screening” and is performed by a trophectoderm biopsy. This involves removing 5-7 cells from the trophectoderm component of an IVF blastocyst embryo, which is the part that will form the placenta. The lab screens the biopsied cells to check whether the embryo has a normal chromosome copy number (known as a euploid) – i.e., checks that you have the right number (46), that none are missing or you have too many and that the chromosomes that are present do not have extra arms, or are missing any arms, or have too long or short arms. If the embryo does not have the correct chromosome copy number, you call it an aneuploid. I find it mind blowing that they can check this at this stage of an embryo’s development – I meant the little chicks are only 5 days old!! Crazy!
PGS is different from PGD screening, which is a method used to screen embryos for any serious inherited diseases. You can read more about it on HFEA’s website.
PGS testing is much debated within the fertility field. Having been under the care now of two senior fertility consultants who are both highly regarded in the field (one on the NHS and one private), I have been given two very different views. The NHS does not offer PGS testing (HFEA sits on the fence on this one, read more here). Our senior fertility consultant on the NHS said: “don’t do it”, and then leaped straight into a conversation about egg donation. Our private consultant highly recommends PGS testing because of my age, having had three failed cycles and no embryos in the freezer. In his experience, the chances of success with PGS normal embryos increase to about 70-75% per round (if everything else – lining, timing – is in order, obviously). If you’re a cynic, you might be thinking it all comes down to cost (NHS vs. private)… and perhaps it does?
Whether you decide to PGS test your embryos or not is a personal decision, but I think it is important to know the pros and the cons before you make a decision (and spend ££££!). This is a good article (admittedly by the company that did our PGS testing), which explains PGS (check out the animation) and the benefits of it. And, this article clearly summarises the criticism of PGS. Both articles are a good read.
Personally, I think part of the problem is that there have not been enough big clinical trials on IVF cycles with PGS testing. I think this is an issue generally in the fertility field because who wants to take part in randomised clinical trials when you’re already preciously rolling the dice?
H and I decided that we wanted to PGS screen our blastocysts in our fourth round… and I am just about to jump on the tube to go to the clinic to find out if any of the five little chicks are euploids…. EEEEEEEK!