A 2024 randomized controlled trial (RCT) found that Zymot-selected sperm didn’t improve embryo euploidy rates, but increased fertilization rates. An important limitation of this study is that it was done in the general IVF population and not in individuals with high sperm DNA fragmentation.
Although most embryo aneuploidies are attributed to the egg, some studies show that sperm can also contribute.
During IVF, semen is processed to concentrate the motile sperm. This is often done using density gradient centrifugation, where viable sperm are separated from dead sperm by spinning (centrifugation).
Another method is microfluidics, where semen is injected into a device and motile sperm travel through a chamber to be collected for insemination. These devices have been shown to select sperm with lower sperm DNA fragmentation (SDF), and have been linked to improved fertilization. A popular microfluidics device is Zymot.
Since Zymot could select sperm with lower SDF, it’s possible that it could improve euploidy rates in embryos compared to conventional sperm processing techniques.
This post is a summary of a study by Godiwala et al. (2024), who compared euploidy rates for embryos that were created from sperm processed using Zymot or density gradient centrifugation. Importantly, this study was done in the general population and NOT in patients with high SDF.
🔗 Original studies are referenced in this post or within the linked Remembryo posts.
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Study details
This section covers key details of how the study was performed, including patient characteristics, how they were treated, and other methods used. For those who aren’t interested in these details, and just want to see the results, you can go ahead and skip this part.
- This was an RCT conducted at a single university-based IVF center in the US between 2021 and 2022.
- This study was funded by a grant from Zymot Fertility.
- Inclusions: Patients were 18-42, had PGT, no donor gametes, no severe male factor infertility or patients requiring testicular biopsy or aspiration.
- This was a sibling egg study, where a patient’s eggs were separated into two groups: one group was inseminated by ICSI using Zymot-processed sperm, while the other group was inseminated with sperm from density gradient centrifugation followed by the swim-up method. Using sibling eggs helps to control for differences between patient egg quality. Sperm was collected fresh (not frozen).
- The primary outcome was the blastocyst euploidy rate.
In terms of sample size, there were a total of 106 patients and 1442 mature eggs. Seventy-seven patients had euploid transfers.
In terms of patient characteristics, the average age was 36.1, with about 20% of patients with unexplained infertility or male factor. About half were using PGT due to advanced maternal age (over 35).
Zymot increases fertilization rate, not other IVF or pregnancy outcomes
This study included 106 patients who had eggs inseminated by ICSI using sperm processed by density gradient centrifugation vs Zymot. There was:
- No difference in euploidy rate (45.7% vs 53.0%, p= 0.34).
- An increase in fertilization with Zymot (69.9% vs 76.0%, p= 0.03).
- No difference in high quality blastocyst formation rate (39.4% vs 38.1%, p= 0.52).
- No difference in the number of blastocysts frozen (2.8 vs 2.5, p= 0.11).
In this study, 31 of the patients had a diagnosis of male factor infertility and 22 had recurrent pregnancy loss. Among these patient groups, there were no differences in euploidy rates, blastocyst formation rates, fertilization rates, or the number of frozen embryos.
There were 77 patients that transferred a euploid. For density gradient centrifugation vs Zymot, there was:
- No difference in clinical pregnancy rate (85.3% vs 91.4%, p= 0.48).
- No difference in ongoing pregnancy/live birth rates (66.7% vs 77.5%, p= 0.32).
- No difference in clinical loss rate (17.2% vs 3.1%, p= 0.09).
Conclusions
This study found that Zymot didn’t lead to an improvement in euploidy rates or blastocyst formation rates, compared to conventional sperm processing techniques. This was also true for couples with male factor or recurrent pregnancy loss.
Zymot also didn’t improve pregnancy rates, but it did improve fertilization rates.
Other studies on the subject have been mixed, with some showing improvements in euploidy rates and other outcomes (linked below).
The Zymot Multi Sperm Separation Device was used, which the authors state is available in the US but hasn’t been researched much. Other studies that have investigated Zymot’s effectiveness have used the Zymot ICSI Sperm Selection Device/FERTILE CHIP, which apparently isn’t available in the US.
It’s important to point out that this study was done in the general IVF population, and not in patients with high SDF, who might show improved euploidy rates. Couples with male factor or recurrent pregnancy loss also didn’t benefit from Zymot, however this study didn’t have the statistical power to properly evaluate these groups.
Regardless, the authors note that using microfluidics for sperm processing is easier and faster than density gradient centrifugation, with likely improvements in fertilization and reduced SDF levels. In other words, if it’s offered and you can afford to use it, it’s not a bad idea to use it!
Related studies
To learn more about this topic, you can check out a number of studies referenced in this study below (7 links):
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.
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