2009-07-01 03:20:39
By Emma Wilkinson
BBC News health reporter in Amsterdam
Having sex every day improves sperm quality and could boost the chances of getting pregnant, research suggests.
In a study of men with fertility problems, daily ejaculation for a week cut the amount of DNA damage seen in sperm samples.
Speaking at a fertility conference, the Australian researcher said general advice for couples had been to have sex every two or three days.
Early results from the trial had already shown promising results.
. Perhaps we have been blaming the women as couples get older but perhaps there's a contribution from the male because we're not behaving as we should be .
Dr David Greening Sydney IVF
But 118 men have now been tested and the benefits for sperm have become clearer.
Dr David Greening, from Sydney IVF, told delegates at the European Society for Human Reproduction and Embryology meeting that eight in ten men taking part showed a 12% drop in sperm DNA damage after the seven days.
Although there was a big drop in sperm numbers from 180 million to 70 million over the week, men were still within the normal "fertile" range.
Sperm also became more active over the seven days with a small rise in motility, he added.
Damage
The theory is the longer sperm hang around in the testes the more likely they are to accumulate DNA damage and the warm environment could also make them more sluggish after a while.
Sperm come under attack by free radicals - small reactive molecules which can damage DNA and cause cell death - in the tube that stores and carries sperm away from the testes.
Further work is needed to work out if daily sex for men without fertility problems has the same benefits but Dr Greening believes it is likely to be the case.
He warns that having daily sex for too long - say a fortnight - would probably cut sperm numbers too much.
But recommended "lots of sex daily" around the time the woman is ovulating.
He said it was best to "keep the river flowing".
As men age they may not have as much sex as they did when they were younger, adding to the problem of infertility, Dr Greening told delegates.
"We are designed to breed in our youth.
"Perhaps we have been blaming the women as couples get older but perhaps there's a contribution from the male because we're not behaving as we should be."
The findings may also have implications for couples undergoing IVF as men are commonly told to abstain from sex for a couple of days to try and boost sperm numbers.
Dr Alan Pacey, a fertility expert at the University of Sheffield, said the finding that daily ejaculation improved the chances of conception was interesting, but it would be wrong to apply the results to all men.
"For example, in cases where men have low sperm counts to start with, daily ejaculations may well reduce the sperm count still further and whilst sperm may be more healthy the reduced numbers could impede the chance of natural conception.
"The best general advice is that if couples are attempting to conceive naturally, intercourse every couple of days will make sure the sperm are as healthy as possible on each occasion.
"However, in preparation for IVF or ICSI treatment, this advice may well change in response to medical test results like DNA damage measurements."
Study: More sex may help damaged sperm
By MARIA CHENG, AP Medical Writer Maria Cheng, Ap Medical Writer . Tue Jun 30, 8:07 am ET
LONDON . For men with fertility problems, some doctors are prescribing a very conventional way to have a baby: more sex.
In a study of 118 Australian men with damaged sperm, doctors found that having sex every day for a week significantly reduced the amount of DNA damage in their patients' sperm. Previous studies have linked better sperm quality to higher pregnancy rates.
The research was announced Tuesday at a meeting of the European Society of Human Reproduction and Embryology in Amsterdam.
Dr. David Greening of Sydney IVF, a private fertility clinic in Australia, and colleagues looked at 118 men who had damaged sperm. Greening and colleagues told the men to have sex every day for a week. After seven days, the doctors found that in 81 percent of the men, there was a 12 percent decrease in the amount of damaged sperm.
Many fertility experts suggest men abstain from sex before their partners have in-vitro fertilization, to try to elevate their sperm counts.
Sperm quality can also be improved if men don't smoke, drink moderately, exercise, or get more antioxidants.
Since concluding the study, Greening says he now instructs all couples seeking fertility advice to start by having more sex. "Some of the older men look a little concerned," he said. "But the younger ones seem quite happy about it."
Experts think sex helps reduce the DNA damage in sperm by getting it out of the body quickly; if sperm is in the body for too long, it has a higher chance of getting damaged.
Some experts said that while Greening's research is promising, it doesn't prove that daily sex for men with fertility problems will actually produce more babies.
Greening said he and his colleagues are still analyzing the study data to determine how many women got pregnant.
"Looking at sperm DNA is just one part of the puzzle," said Bill Ledger, a professor of obstetrics and gynecology at the University of Sheffield, who was not connected to the research. "Maybe this will improve pregnancy rates, but we still need to do more studies."
Ledger said instructing couples with infertility problems to have more sex could stress their relationship. "This may add even more anxiety and do more harm than good," he said. He said couples shouldn't feel pressured to adjust their sex lives just for the sake of having a baby.
Greening said the study's findings were ultimately very intuitive. "If you want to have a baby, our advice is to do it often."