Researchers in a 2020 study found that women with increasing age had reduced positive beta-hCG, clinical pregnancy and live birth rates when transferring a single euploid embryo.
PGT-A is effective in identifying euploid embryos for transfer and leading to high live birth rates, but it’s not clear if success rates decline with advancing age.
Check my complete guide to PGT-A to get more background on (aka PGS testing).
Reig et al. (2020), in their retrospective study, compared pregnancy outcomes in 8,175 women of various ages who transferred a single euploid embryo. This study took place between 2011 and 2018 at a single IVF center in the US.
The 8,175 women were split into five age groups:
- <35 (3,789 women)
- 35-37 (2,200)
- 38-40 (1,624)
- 41-42 (319)
- >42 (243)
Key information:
- All transfers involved a single frozen euploid.
- No donor egg cycles.
- No uterine cavity abnormalities.
In terms of baseline characteristics, there were differences in BMI, paternal age, antral follicle count, AMH, cycle day 3 FSH, cycle number, the day the embryo was frozen (day 5/day 6) and embryo quality. These were all controlled for in their adjusted statistical model.
This study refers to implantation rate as a positive hCG 9-10 days after euploid transfer. This is a bit of an unusual definition (it’s usually presence of a gestational sac), so to avoid confusion I’ll be indicating this as “positive beta-hCG.”
🔗 Original studies are referenced in this post or within the linked Remembryo posts.
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Implantation potential of euploids decreases with advancing maternal age
The positive beta-hCG, pregnancy and live birth rates after transferring a single euploid are shown below. This was statistically significant (p<0.001).
After statistical adjustment to control for confounders (BMI, embryo quality, etc. as indicated above), the odds ratio [95% CI] for the positive hCG rates were:
- <35: reference
- 35-37: 0.9 [0.78-1.03] – not significant
- 38-40: 0.85 [0.73-0.99] – significant
- 41-42: 0.69 [0.52-0.91] – significant
- >42: 0.69 [0.5-0.94] – significant
This kind of analysis is done to control for differences in embryo quality, BMI, etc. (confounders). For example, in women >42, the odds of having a positive hCG following a single euploid transfer is 0.69 times the odds in someone <35. In other words, the odds of having a positive hCG is 31% lower (100%-69%=31%) in women >42 compared to women <35, after controlling for confounders.
So there was a reduction in positive hCG rates after euploid transfer as age increases, which corresponded to a decreased clinical pregnancy and live birth rate. In other words, fewer euploids were implanting as age increased.
They found a similar decrease when looking at clinical pregnancy rates:
- <35: reference
- 35-37: 0.93 [0.83-1.05] – not significant
- 38-40: 0.86 [0.76-0.98] – significant
- 41-42: 0.74 [0.58-0.94] – significant
- >42: 0.71 [0.54-0.94] – significant
And live births rates:
- <35: reference
- 35-37: 0.9 [0.8-1.01] – not significant
- 38-40: 0.84 [0.74-0.95] – significant
- 41-42: 0.74 [0.58-0.95] – significant
- >42: 0.76 [0.58-1] – significant
Conclusions
This study found decreasing positive beta-hCG, clinical pregnancy and live birth rates with advancing female age after a single euploid embryo transfer, even after controlling for the day the embryo was frozen (day 5 vs day 6), its quality, and other factors.
This study contradicts previous research by Irani et al. (2019) which found no effect on pregnancy outcomes when transferring euploids in women with increasing age, possibly due to their smaller sample size and use of both double and single euploid transfers.
Age is generally believed to have no effect on a uterus’ ability to sustain embryo implantation, but previous studies may have overlooked the impact of an aging uterus on implantation rates because of higher aneuploidy rates in women with advanced age, the authors write.
A limitation is they didn’t control for the year that PGT-A was performed. Since this spans 2011 to 2018, older PGT-A technology may have been limited in resolving mosaics from euploids, which may have a lower success rate.
Reference
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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.
Related posts:
Study examines potential of PGT-A on poor quality embryos
PGT-A meta-analysis finds live birth rates only improve with older patients
Study evaluates factors affecting pregnancy outcomes after euploid transfer
Meta-analysis combines 74 studies to examine factors linked to euploid transfer success
Study compares PGT-A outcomes for patients with different diagnoses
IVF outcomes following aneuploid embryo transfer
A look at how PGT-A results change with age, using data from over 86,000 biopsies
Examining live birth rates in IVF cycles with 5 or less follicles