Couples undergoing fertility treatments do not need to abstain from sex for up to a week to improve their chances of success, according to Israeli researchers.
Their findings to the conference in Madrid on infertility challenged standard medical advice.
Men are usually advised to avoid sex for two to seven days before some types of fertility treatment, to increase semen volume and sperm count.
But scientists at Soroka University and Ben-Gurion University of the Negev, Beersheba, said this was unnecessary.
"Our data challenge the role of abstinence in male fertility treatments," Dr Eliahu Levitas told a meeting of the European Society of Human Reproduction and Embryology.
Infertility affects about one in six couples because of a problem with the woman, the man or both partners. Male infertility results when no sperm, or not enough, is produced or if their shape or movement is abnormal.
"What we have found is not so relevant to (treatments) where only a single sperm is injected into the egg, but for those treatments where we are trying to get the best possible sperm quality for intra-uterine insemination," Levitas said, referring to a fertility technique in which sperm is injected into the uterus.
The World Health Organization recommends sexual abstinence for two to seven days before fertility treatment.
The researchers tested more than 7,200 semen samples for sperm concentration and shape and counts of motile, or active and moving, sperm.
About 6,000 samples were from men being tested or treated for infertility who had avoided sex for up to two weeks. More than 4,500 had normal sperm counts. The rest had reduced counts ranging from mild to severe.
The study found the volume of semen increased after 11 to 14 days of abstinence but the shape and the form of the sperm deteriorated.
In men with low sperm counts, the proportion of motile sperm fell from day two onwards and reached a low at day six.
"Semen volume was directly and significantly correlated with duration of abstinence, while sperm motility was inversely and significantly related to abstinence in oligozoospermic (reduced sperm count) samples only," Levitas said.
Nearly 5,000 doctors, scientists and fertility experts from 95 countries attended the four-day Madrid conference from June 29-July 2.
(Agencies via Xinhua July 3, 2003)
