PGS (PGT-A) success rates

In this post we’ll learn more about IVF with PGS success rates for euploid embryos. We’ll also look at the chances of getting a euploid based on age, the impact of embryo grade and the day it was frozen (Day 5, 6 or 7), and how rebiopsies or thaw and biopsies fare for success rates.

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Chances for getting a euploid embryo

A recent 2019 study looked at 130,000 biopsies by NGS tested (this is the current testing method):

• Donor eggs: 63.1% euploid
• <35 years: 59.5% euploid
• 35-37 years: 50.3% euploid
• 38-40 years: 38.3% euploid
• 41-42 years: 26.8% euploid
• 43-44 years: 24% euploid
• They also found that the chance of getting a complex abnormal embryo increased with age

Demko et al. (2016) looked at over 18,000 Day 5 embryo biopsies (using the older SNP technology) and reported the chances of an embryo being euploid (based on age):

• ≤ 35: 61%
• 36: 56%
• 37: 51%
• 38: 46%
• 39: 41%
• 40: 37%
• 41: 32%
• 42: 27%
• 43: 22%
• 44: 17%
• 45: 12%

So up until 37 there’s about a 50% chance of each blastocyst being a euploid, this cuts in half to about 25% at 42.

I wanted to point out the standard deviation of this data is large, roughly 30% for each group. So most <35 women are between 30-90% chance of euploid (61% is the average).

They also reported the number of blasts biopsied. For <37, this was about 5, for 37-40 about 4, and for >40 about 3 (so older women tend to produce fewer blasts).

They also provided information for the chance of getting no euploids per cycle:

• ≤ 35: 12%
• 36: 14%
• 37: 15%
• 38: 18%
• 39: 22%
• 40: 26%
• 41: 32%
• 42: 39%
• 43: 48%
• 44: 57%
• 45: 66%

So as age increases, the chances of getting a euploid embryo drop. By 40 there’s about a 1 in 4 chance of not getting a euploid and by 43 this doubles to half. Another study agrees with these data (Franasiak et al. 2014).

Success rates with chromosomally normal embryos

Simon et al. (2018) looked at about 650 transfers of PGS tested euploid embryos (based on SNP technology) across various ages:

• <35: 66% live birth per transfer
• 35-37: 71%
• 38-40: 60%
• 41-42: 49%
• >42: 72%
• Donor eggs: 52%

So it looks like the success rates hover around 60-70% in most cases, with women >42 having about a 50% live birth rate per transfer.

Note that this is per transfer data. This means that these women had euploid embryos for transfer. But what about the women who didn’t get blasts? Or they did but they were all aneuploid? To count these women in, we can look at the per retrieval data:

• <35: 64% live birth per retrieval
• 35-37: 54%
• 38-40: 40%
• 41-42: 17%
• >42: 20%
• Donor eggs: 52%

Now when we look at everyone the stats look much different! Because all the women who didn’t have embryos to transfer are now included and lower the overall success for that age group. For these groups, about 50% of biopsies had no euploid embryos. The per retrieval statistic helps to see the chances before PGS testing.

Be sure to read the next two sections to get an idea of how grades and growth rates (Day 5, 6, 7) affect IVF with PGS success rates, as well as this section further down.

Embryo grades and PGS success rates

Thought just because your embryo is euploid that grades don’t matter anymore?

Not exactly! PGS/PGT-A success rates can vary.

Zhao et al. (2018) looked at euploid embryos (aCGH/SNP) in women <35:

• Graded as excellent (AA) or good (AB or BA) = 50% live birth
• Average (AC, CA or BB) = 42% live birth
• Poor (BC or CB) = 25% live birth

Irani et al. (2017) had similar results to above (aCGH, women <35):

• Graded as excellent: 84% ongoing pregnancy, 0% miscarriage
• Good: 62% ongoing pregnancy, 3% miscarriage
• Average: 56% ongoing pregnancy, 11% miscarriage
• Poor: 36% ongoing pregnancy, 19% miscarriage 

Capalbo et al. (2014) found no difference in ongoing pregnancy between grades (about 50% for each category). However, their sample size was small.

Check out my complete guide to embryo grading and success rates to learn more about embryo development, grading and success rates.

PGS success rates for Day 5, 6, or 7

Embryos grow at a certain rate:

• Day 3 = 8 cells
• Day 5 = blastocyst

Some are faster, and some are slower. How fast embryos grow has an impact on success rates for untested embryos. Generally, Day 5 embryos perform better than Day 7 embryos.

If you want to read more about about success rates for untested embryos, go to my embryo grading and success rates post.

So what if the embryos are euploid? Does it still matter?

Liebermann et al. (2017) found that Day 5 euploids had a higher ongoing pregnancy rate vs Day 6 euploids (51.9% vs 32.7%).

Whitney et al. (2016) found no statistically significant difference in ongoing pregnancies between Day 5 and 6 euploids (78.6% vs 67.4%), but this was reduced by Day 7 (43.8%).

Capalbo et al. (2014) found no difference in ongoing pregnancies with Day 5 or 6 euploids (about 50%). There was also no difference with Day 7, although the sample size was very small.

Like embryo grades in the previous section, it looks like IVF with PGS success rates may vary based on how fast the embryo develops, particularly for Day 7.

Rebiopsy

Inconclusive or No Result biopsies may require a second round of biopsy aka a rebiopsy.

Obviously this is not an ideal situation but sometimes this happens. In this case the clinic will need to:

• Thaw the embryo and culture it until it can be biopsied (this may take a few hours to a day)
• Perform another biopsy
• Freeze the embryo embryo again
• If the 2nd test comes back euploid and you transfer, another thaw will need to be done

So the embryo would have to go through multiple rounds of freezing/thawing/biopsy, and this might have an impact on it’s potential.

Neal et al. (2018) found a slight reduction in live birth rate compared to single biopsied embryos (50% vs 58%), but this was not statistically significant.

In a small study, Bradley et al. (2017) found a reduction in embryo survival (from 98% to 93%) and a reduction in live birth rate (50% to 27%).

Another small study found no difference in survival or live birth rates with rebiopsied embryos (Cimadomo et al. 2018).

There isn’t much data on it, and 2 of the 3 studies found no difference, so it isn’t exactly clear. Your clinic may have a better idea of how things work in their hands.

If you want to read more about rebiopsying embryos, check out my archives for embryo rebiopsy

Thaw and biopsy

So maybe you’ve had a cycle and your embryos are frozen, and now you want them biopsied. This can be done! It will involved thawing your embryos, biopsying, then re-freezing and ultimately re-thawing if the embryo is euploid and you want to transfer it.

Does this harm the embryo or reduce its potential for success?

Bradley et al. (2017) found no difference in survival rates of embryos that were thawed and biopsied, then refrozen. They found a reduction in live birth rates (50% to 39%), although this was not statistically significant (it was from a small study).

Aluko et al. (2018) found a reduction in clinical pregnancy when embryos were thawed, biopsied and re-frozen (the odds were about half).

These studies were particularly small so drawing conclusions isn’t really possible yet. More studies need to be done. For now it’s probably best to avoid having to thaw and biopsy if possible. Your clinic may have a better idea!

For more up-to-date information on this topic check out my other posts that are tagged with Embryo rebiopsy.

Mosaic embryo success rates

I have a whole page dedicated to mosaic embryos. Alternatively you can check out my website’s tag for mosaic embryos here.

 

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About Embryoman

Embryoman (Sean Lauber) is a former embryologist and the founder of Remembryo, an IVF research and fertility education website. After working in an IVF lab in the US, he returned to Canada and now focuses on making fertility research more accessible. He holds a Master’s in Immunology and launched Remembryo in 2018 to help patients and professionals make sense of IVF research. Sean shares weekly study updates on Facebook, Instagram, and Reddit regularly. He also answers questions on Reddit or in his private Facebook group.

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