Sperm DNA fragmentation associated with lower embryo quality and implantation

Researchers in a 2019 study compared IVF outcomes from men with low or high sperm DNA fragmentation, finding that high SDF patients had poorer quality blastocysts and a higher chance of miscarriage.

A semen analysis involves measuring different sperm parameters:

• Semen volume
• Sperm count (how many sperm)
• Sperm motility (what % of sperm are moving)
• Morphology (what % of sperm appear normal)

The thing is…the semen analysis isn’t all it’s cracked up to be. 15% of infertile men have semen parameters within the normal range (Borges 2019) – so there’s likely something else going on.

Sperm DNA fragmentation (SDF) is another parameter that can be measured. The DNA inside sperm can be broken, or fragmented:

These breaks in the DNA can cause interruptions in the DNA sequence. A recent paper (Borges 2019) looked at how high SDF compared to low SDF in terms of IVF success rates and embryo quality.

When it comes to measuring sperm DNA fragmentation, there’s a lot of choices for what test to use. In this study, they used a test called the sperm chromatin dispersion (SCD) test that makes picking out sperm with fragmented DNA pretty easy:

They counted 200 sperm to get the % of SDF and used 30% as their cutoff for low (<30% SDF) vs high (>30% SDF). Then they measured different IVF outcomes between these groups:

• Fertilization rate didn’t change
• High quality day 3 embryos decreased with high SDF (36.47% vs 23.89%)
• Blastocyst rate decreased (56.25% vs 39.01%)
• Blastocyst quality decreased
• Implantation rate decreased (46.09% vs 33.21%)
• Pregnancy rate didn’t change
• Miscarriage rate increased with high SDF (17.8% vs 39.9%)

So it looks like high SDF was associated with poorer embryo quality, reduced implantation and higher miscarriage. Fertilization and pregnancy rates were the same.

Some of the shortcomings of this research included:

• Small study (433 men with low SDF, 42 men with high SDF)
• Only correlative data – no evidence that high SDF caused the above, only that it was associated
• Used the SCD test which is cheaper and easier to perform but considered inferior to the “gold standard” SCSA test

Reference

Borges E Jr, Zanetti BF, Setti AS, Braga DPAF, Provenza RR, Iaconelli A Jr. Sperm DNA fragmentation is correlated with poor embryo development, lower implantation rate, and higher miscarriage rate in reproductive cycles of non-male factor infertility. Fertil Steril. 2019 Sep;112(3):483-490. doi: 10.1016/j.fertnstert.2019.04.029. Epub 2019 Jun 11. PMID: 31200969.

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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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