Why PGS Embryo Testing Is A Mistake
Photo by Asdrubal luna on Unsplash
Earlier this year, I considered making my fertility experience public so that I could share helpful tips along the way. For example, after an egg retrieval, you’re supposed to rest and avoid exercise. For some women, recovery is a breeze; for others, it can take a few weeks and cramping can be extremely uncomfortable. After my first egg retrieval, it was incredibly difficult to get up after lying down. It hurt just to sit up.
Then I learned a tip: a woman is best off lying on pillows at an incline, so that the harvested follicles don’t fill up with fluid. This simple change took my level of cramping from a 8 from one retrieval to a 4 for the next cycle. That’s a big improvement but it didn’t feel like a big enough reason to share such a personal experience of trying to have a baby.
Why we Initially chose to do PGS testing
K and I thought that PGS testing was the right move. After going through 3 IVF cycles, and 2 egg retrievals, we ended up getting 4 embryos. Those 4 embryos were kept frozen until we found a surrogate mother. We had 2 embryos transferred to the surrogate; it was unsuccessful. Since we didn’t have the embryos tested, we didn’t know why it didn’t work. We didn't know if there was an issue with the surrogate or if the eggs weren’t viable.
We decided to test the remaining 2 embryos. The results were disappointing; both were found to be abnormal. The first embryo has 4 extra chromosomes and the second embryo has one extra and one missing chromosome from different pairs.
Why it’s a mistake to do PGS testing:
A few weeks later, a friend was kind enough to send me a very informative article: A New Last Chance: There could soon be a baby-boom among women who thought they’d hit an IVF dead end. It is a long article, so here is a link to a printout with my highlights and markings of things I found most important and interesting. I’ve also listed some highlights from the article below:
Aneuploid embryo: An embryo that has too many or too few chromosomes can result in a genetic disability. (Page 1)
“…an abnormal embryo is simply “destined to fail” – either it won’t implant or, if by chance it does, the resulting pregnancy will almost certainly end in miscarriage.”
Almost 90% of embryos produced by women older than 42 are aneuploid embryos. (Page 2)
PGS, pre-implantation genetic screening, uses a laser to pry five or six cells from the outside of each day-five embryo for lab analysis. It is surprisingly common for one chromosome to be missing (monosomy) or for there to be an extra chromosome (trisomy). “If even one of the cells turns out to be abnormal, the test registers as abnormal. The entire embryo is considered aneuploid, and it is not transferred.” (Page 2)
A growing number of doctors believe how good the embryo looks is more important than if it is an aneuploid. An embryo that looks good means “the cells along the outer wall were evenly spaced and symmetrical, and a little clutch of cells in the interior — the part destined to become the baby — appeared tightly packed and well organized.” (Page 2)
“….transferring an abnormal embryo wasn’t without risks: not only the obvious possibility of miscarriage and even a genetically abnormal child, but subtler issues of “emotional trauma,” of getting pregnant but not knowing if the pregnancy was normal until a week-ten prenatal test.” (Page 3)
“…PGS testing misdiagnosed too many embryos as abnormal and that many of those “abnormal” embryos might be more viable than anyone thought.” (Page 3)
“In order to understand why the PGS test results could be inaccurate, it helps to think of an embryo as a classic soccer ball…. Many soccer balls have a mix of black and white facets on the outside of the ball; many embryos at day five similarly have a mix of white (euploid) and black (aneuploid) cells on their outer surface. If you biopsy from a white part, you’ll think the embryo is entirely normal; if you biopsy from a black part, you’ll think it’s entirely abnormal. If you happen to biopsy at a seam, you might get a mix of black and white cells. Embryos that display this mix are known as “mosaics,” but the version of PGS that entered use around 2010 still deems these embryos abnormal. “The fact that it looks like a soccer ball means that you’re going to get potentially a different biopsy [result] every time you do it,” says Paulson.” (Richard Paulson, USC department head of reproductive medicine and current president of the ASRM.) (Page 6)
“First, the cells from the outer wall, the ones biopsied for the PGS test, aren’t even destined to become the baby; instead, they’ll go on to form the placenta. Zernicka-Goetz found that abnormal cells on the outer shell, the black spots of the soccer ball, can persist even as the part of the embryo destined to become the fetus weeds out abnormal cells. Moreover, if human embryos are anything like mouse embryos, the self-correcting changes that Zernicka-Goetz observed can occur later in embryonic development, after PGS testing is conducted in human embryos.” (Page 6)
The initial version of the PGS test offered between the late ‘90s to 2010 “significantly impaired the ability of day-three embryos to implant” and “actually did harm.” (Page 7)
“He worries that, like the ‘90s version of PGS, the newer tests may do damage to the embryo “as a result of the biopsy process” and says “there is ample indirect evidence, circumstantial evidence, that you in fact are doing harm.” (Richard Paulson, who heads the department of reproductive medicine at the University of Southern California and serves as the current president of the ASRM). (Page 8)
There have been no reports of genetic abnormalities of the approximately 100 babies born to date following abnormal transfers. Some doctors warn that it’s too soon to tell whether there are any long-term health effects; other doctors think the odds are very low. (Page 7)
Most embryos from IVF were never tested and mosaic embryos are very frequent, so it’s estimated that millions of them have been unknowingly transferred for decades. (Page 8)
“…a multi-center study reporting 58 successful pregnancies out of 143 mosaic transfers (a success rate of 41 percent).” (Page 8)
“…Pasquale Patrizio, head of fertility medicine at Yale University, and Sherman Silber of St. Luke’s Hospital in St. Louis recently suggested that “perhaps the best advance now for IVF is to take a step backward” and simply transfer day-five embryos without testing them first…” (Page 9)
Halfway through reading the PGS article, I was in tears. I didn’t know if the remaining two embryos we had tested and declared abnormal were discarded or if they remained in storage. The thought of throwing away what could have been good, viable embryos makes my chest heavy.
I tried to hold it together to call the fertility office and see if they still had the 2 tested embryos. And they did--our fertility office kept the eggs frozen as backup! We spoke with our doctor and agreed that the plan moving forward is to try IVF again. If the attempt(s) fail, we would consider transferring the saved embryos. We were lucky to have it work out OK so far and no potential viable embryos were dismissed. (There is still debate on whether the newer PGS testing may do damage to embryos or not.
But to think of all the tens of thousands of other embryos tossed away because of PGS testing--after all the time, effort, money and most importantly the hope for a baby--is just heartbreaking. “…mainstream doctors consider 40 percent to be a reasonable figure, suggesting that in the U.S. alone, nearly 45,000 embryos may have been classified as abnormal and ticketed for disposal in a single recent year, many of which may have produced a normal baby,”
I was hesitant to share our fertility experience until I learned that PGS testing on embryos is a mistake. But after that ordeal, I couldn’t withhold such important information. I’ve decided to share what K and I are going through, so that what we learn along the way could be useful to other couples.
Note: When I read the article for the first time, I printed it out and made quick notations on paper and highlighted different points than what is listed above. If you are considering PGS testing, read the article in full before making your decision.