* Stress not linked to chance of fertility treatment success
* Infertility affects 9 to 15 pct of childbearing population
* Study should help dispel myths about pregnancy success
By Kate Kelland
LONDON, Feb 25 (Reuters) - Women trying to get pregnant via IVF or other assisted reproduction techniques do not reduce their chances of success if they are emotionally distressed, according to a large scale analysis published on Friday.
In a review of data covering more than 3,500 women undergoing in vitro fertilisation or other fertility treatments, British researchers found no difference in pregnancy success rates of women who were stressed and those who were not.
"These findings should reassure women that emotional distress caused by fertility problems or other life events co-occurring with treatment will not compromise their chance of becoming pregnant," said Jacky Boivin of Cardiff University's school of psychology, who led the study.
Infertility is a worldwide problem that affects 9 to 15 percent of the childbearing population, experts say. More than half of those affected will seek medical advice in the hope of eventually being able to become a parent.
IVF involves fertilising an egg with sperm in a lab before implanting the embryo into a woman's womb, and can cost a patient many thousands of euros or dollars.
In research published last month, fertility specialists said that in the United States and Britain, IVF is successful in about a third of women under 35 years old, but in only five to 10 percent of women over the age of 40. [ID:nLDE70213H]
Many infertile women believe that emotional distress is a factor in not getting pregnant naturally or in lack of success with fertility treatment.
But Boivin's team, whose work was published in the British Medical Journal, said that view was largely based on anecdotal evidence and often repeated fertility myths such as "relax and you'll get pregnant".
Conducting a large-scale review known as a meta-analysis, the researchers looked at data from 14 studies involving 3,583 infertile women from the United States, Australia, Britain Belgium, Canada, Denmark, Sweden, Turkey, and other countries who were undergoing fertility treatment.
The women had been assessed for anxiety and stress before their treatment, and Boivin's team compared data for women who achieved pregnancy to those who did not.
The results showed emotional distress was not associated with whether or not a woman became pregnant, Boivin said. (Editing by Diana Abdallah)