"This means that we can use these findings to reassure women and this information should, in itself, help to reduce their stress and worry levels," said lead author Dr Lisbeth Anderheim whose team's research is reported today (Thursday 25 August) in Europe's leading reproductive medicine journal Human Reproduction.
Past research on the effect of psychological stress on IVF success has been conflicting, with some studies finding an association and others not. But, support for a causal link between stress and IVF results was often weak, according to Dr Anderheim, midwife and PhD student at the Department of Obstetrics and Gynaecology at Sahlgrenska University Hospital in G?teborg (Gothenburg).
The new research has the strength of being prospective and therefore does not rely on answers given after the patients found out whether their treatment was successful. A month before treatment 166 women answered extensive questionnaires evaluating their well-being. These covered a wide range of emotions, their general health, their relationship with their partner, their lifestyle and outlook on life and the intensity of their desire for children. A second questionnaire timed just before their eggs were retrieved was answered by 151 of the women. A total of 139 women had embryos available for transfer ? 58 conceived and 81 did not.
The results of the pre-treatment questionnaire showed no difference between those who became pregnant and those who didn't. The questionnaire was a proven method for measuring well-being ? the Psychological General Well-Being (PGWB) index. The patients' scores were in line with Swedish reference values, reflecting the fact that the women were in good psychological health at the start of treatment. There was also no significant difference between the two groups on an additional test designed specifically to assess 14 emotions often expressed by infertility patients.
The analysis of the second questionnaire answered just before egg retrieval again showed no difference between those who conceived and those who didn't.
"The only variable that was significantly associated with pregnancy was the number of good quality embryos transferred,' said Dr Anderheim.
Dr Anderheim said the good psychological well-being of the patients prior to treatment was somewhat unexpected and did not correspond with earlier clinical impressions. So, it was possible that the patients were keeping their worries to themselves because they had great expectations and were giving answers that were more positive than they felt. Neither could the researchers totally rule out that the lack of a link between stress and outcome might have been due to lack of sensitivity in the methods used, although the PGWB method was proven to be valid and reliable and the other questionnaire used had been devised specially for the study to pick up aspects of stress identified among infertility patients.
She said the timing of the first questionnaire was chosen because they wanted to study the women's psychological status before treatment. The timing of the second just prior to egg retrieval was chosen because patients often express anxiety and stress at that point. It may, she conceded, have been valuable also to have questioned patients at the point the embryos were transferred, which is known to be a time of heightened tension.
However, the fact that it was impossible to establish a link in a prospective study between stress and the chances of conceiving via IVF was encouraging.
"During IVF treatment patients frequently ask about the relationship between psychological stress and outcome and often express worries that their own stress might have a negative influence, so the fact that our prospective study did not indicate any relationship is reassuring. This is a positive message we can give our patients to help decrease their stress at this time." Dr Anderheim concluded.