Stress levels are unlikely to affect whether or not a woman becomes pregnant following fertility treatment despite anecdotal reports, a review suggests.

Researchers from Cardiff University and the University of Thessaloniki in Greece reviewed 14 previous studies that investigated pre-treatment stress in over 3,500 infertile women undergoing a single cycle of IVF. The authors then compared data on emotional distress levels for women who became pregnant and those who did not. The review, published in the British Medical Journal, found no association between levels of emotional distress and the success of fertility treatment.

The studies reviewed used various ways of measuring anxiety or depression and included women undergoing several kinds of fertility treatments. Women were assessed before treatment for anxiety or depression and then the success or failure of their treatment was recorded.

Lead researcher Professor Jacky Boivin, from the Fertility Studies Research Group of Cardiff University, said the meta-analysis 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'.

Clare Lewis-Jones, chief executive of the charity Infertility Network UK, said: 'Whilst stress may not impact on the success of treatment, the need for patients to receive support and understanding should not be ignored'.

Around one third of UK couples end assisted reproductive treatments early, many due to the stress involved in undergoing treatment.