Objectives To investigate if magnetic resonance imaging (MRI) influences male reproductive hormones. The use of MRI is increasing around the world and the possible adverse effects on reproductive health of electromagnetic fields (EMF) in MRI are not previously studied. Previous articles have suggested that radio frequency (RF) electromagnetic fields may influence on male reproductive hormones follicle stimulating hormone (FSH) and luteinizing hormone (LH), and that this may cause reduced sperm quality.

Methods A randomised balanced cross-over study using real and sham MRI scan among 24 healthy male volunteers were conducted. Serum-blood samples of Inhibin B, testosterone, LH, FSH, sex-hormone binding globulin, oestrogen, prolactin and thyreotropine were taken immediately before and after the different scans and at a control session without any scan. Questionnaire data was gathered regarding possible confounding factors among the participants at each session. The RF EMF exposure caused by the MRI scanner was described as RF estimates for each sequence driven during the scan.

Results When investigating the hormone levels immediately before and immediately after the scan we found no differences, neither in the MRI scan setting nor in the sham setting. We also investigated if the hormones changed differently in the MRI setting versus the sham setting, but found no differences. We could neither find an effect after 11 days, which was the average number of days between the different sessions.

Conclusion EMF exposure during a MRI did not cause changes in male reproductive hormones. Adverse effects on other endpoints than male reproduction or possible chronic effect of multiple MRI scans have not been investigated in this study. To evaluate this, further studies should be carried out.