Will this research from the Center for Reproductive Medicine at China Medical University (Li and Wang's lab), published in the journal Molecular and Cellular Proteomics, challenge the advice currently given by doctors in fertility clinics? Today, men who are trying to conceive are advised to abstain between conception efforts. But the team who worked with nearly 500 couples conclude that using sperm after a short period of abstinence of less than 3 hours increases the chances of conception.
The objective of the study was to determine whether the length of time a couple waits between conception efforts or fertility treatment cycle can impact success rates. Indeed, if today, doctors in fertility clinics advise rather to abstain between each treatment, Drs Da Li and XiuXia Wang, clinical researchers at the Center for Reproductive Medicine at Shengjing Hospital in Shenyang, suggest changing the IVF protocol.
The team worked with nearly 500 couples to determine whether the length of time a couple waited between conception efforts could alter their success rate.
Sperm is more fertile 3 hours after:
- the researchers confirm here the conclusions of previous studies showing that the sperm produced shortly after the most recent ejaculation, that is to say approximately 3 hours later, contains spermatozoa which are faster and more mobile than after an abstinence of several days;
- using a technique called mass spectrometry to examine the protein composition of samples, the team identifies major molecular differences. The majority of affected proteins are involved in cell adhesion, a function that sperm need to fuse with eggs.
- Differences between the two sample types are also seen in proteins involved in sperm motility and metabolism, particularly in proteins that regulate reactive oxygen species, a byproduct of cellular energy production. . Although reactive oxygen species are necessary for some normal sperm functions, an excess can damage sperm genetic material. The researchers point out that the longer the sperm, the more vulnerable they are to DNA damage by reactive oxygen, and this vulnerability is a barrier to their ability to form a viable embryo.
Do the observed changes affect fertility? The team proceeded, for IVF, as usual with the two types of samples, for the 500 couples, using them to generate and then implant embryos. While the “typical” live birth rate in a cohort of this size is around 30%, in the experimental cohort, linked to only a few hours of abstinence, the live birth rate is higher by a third.
Opt for frequent sex around the time of ovulation? These data suggest that couples with relatively normal (sperm) characteristics should have frequent intercourse around the time of ovulation. “It could make all the difference,” sum up the researchers. The team plans to continue working with patients and performing further research to better identify differences between sample types.
“Promising and exciting prospects for future parents”.
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