Rhiannon Ingle
According to new research, more frequent ejaculations may actually help raise men’s fertility levels.
Contrary to previous beliefs, a large analysis from the University of Oxford researchers suggests that sperm declines the longer it sits in the body.
The researchers reviewed 115 studies covering nearly 55,000 men, plus animal data, and found that more abstinence meant more DNA damage, oxidative stress, lower motility, and reduced viability.
"In men, the negative effects we found on sperm DNA damage and oxidative damage were large-ish, so we are confident that this is a biologically meaningful and important effect," Dr Krish Sanghvi, a biologist at the University of Oxford and lead author on the study, told The Guardian.
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Current World Health Organisation guidance advises two to seven days of abstinence to maximise sperm count, mainly for testing, but this new research points to a much shorter gap.
Around 48 hours between ejaculations was linked to better sperm quality.
Fertilisation success itself did not change, but Dr Sanghvi called the effect 'a biologically meaningful and important effect'.
The findings line up with a recent IVF trial of 453 couples.
Pregnancy rates were 46% when men abstained for under two days, versus 36% for those who waited two to seven.
"All we recommend is that clinicians and couples reconsider whether long abstinence is always good, because abstinence leads to deterioration in sperm quality," Sanghvi said.
"If sperm quantity is the only thing that matters for a clinic or couple, then sexual abstinence is not necessarily a bad thing. But usually fertilisation success will be determined not only by how many sperm there are but the quality of the sperm too, for example, in IVF."
Meanwhile, Allan Pacey, a professor of andrology at the University of Manchester, told the outlet: "There has been growing evidence in recent years that a shorter abstinence time might be beneficial when undergoing assisted reproduction such as IVF.
"This is because with a short abstinence time, the sperm are fresher, more motile and have lower levels of DNA damage.
"The two-to-seven-day abstinence rule is important to stick to for men undergoing semen analysis at the diagnosis stage, as it allows results to be compared over time between laboratories and against international benchmarks. But it isn’t as important when IVF treatment is actually taking place."
The professor added: "For assisted reproductive technology (ART) treatments, it’s having the freshest, most healthy sperm that is probably more important. We can do IVF treatment with a low number of sperm, and even lower if we do ICSI (intracytoplasmic sperm injection), so it isn’t as necessary for men to save up their sperm in the way that we once thought."