MALE FERTILITY: It would be at its peak 3 hours later

 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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STRESS: It reduces fertility in women

 If the link between higher stress levels and lower chances of conception is indeed a causal association, concludes this study from Boston University, part of this association could be linked to a reduction in the frequency of sexual intercourse. and increased irregularity of the menstrual cycle. But, in summary, stress is confirmed here, in the American Journal of Epidemiology, as a serious factor in reducing fertility in women.

 

20 to 25% of women and 18 to 21% of men of childbearing age report feeling daily psychological stress, say these Boston researchers. But, while previous studies have already suggested that stress can reduce the chances of conception, few studies have examined this association in the general population. This new study confirms that higher levels of daily stress are indeed associated with reduced chances of conception in women. But not in men.

 

The study does not prove that stress causes infertility, says Amelia Wesselink, lead author of the study, but it does add to the evidence for the value of incorporating mental health care into counseling women before design.

This is an analysis of data from the Presto study, a cohort that follows couples for 12 months or until pregnancy. The researchers followed 4,769 women and 1,272 men with no history of infertility who had not tried to conceive for more than 6 menstrual cycles. The researchers rated their participants' perceived stress using a stress scale ranging from 0 (never) up to a total of 40, indicating a higher level of perceived stress. The researchers also took into account a range of demographic and behavioral factors, including ethnicity, household income, diet, sleep and frequency of sexual intercourse. The analysis finds that:

• on average, baseline perceived stress scores are about 1 point higher in women than in men;
• mean perceived stress scores in women remained relatively constant over 12 months of follow-up;
• women with a perceived stress score >25 have a 13% reduced chance of conceiving vs women with a perceived stress score <10;
• this association is stronger in women who had been trying to conceive for 2 menstrual cycles before joining the cohort, vs in women who had been trying for at least 3 cycles before joining;
• the association is also stronger in women younger than 35 years.

 

 

The researchers thus confirm a link between higher stress levels and lower chances of conception, however they also show that this link could be partly explained by a decrease in the frequency of sexual intercourse and an increased irregularity of the menstrual cycle. .

 

Discordance of stress in the partner also affects fertility: The association between the perceived stress score and the probability of conceiving is not found in men. However, couples are found to be about 25% less likely to conceive when the men's perceived stress score is <10 and the women's is >20. The authors call this pattern “partner stress mismatch,” a pattern that may also affect the likelihood of conception, although at this stage this remains a hypothesis to be confirmed.

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