The effect of a coping-ineffectiveness of coping construct and of psychoendocrine stress responses upon the outcome of in vitro fertilization treatment was investigated in 40 women. Women with a high Zung depression score, high active coping, high avoidance, and a high expression of emotion have lower pregnancy rates. The mechanisms for this personality effect are not clear, although the desensitization-stimulation process (FSH, E2 concentrations) seems to be involved. The psychoendocrinological responses to the stress of oocyte retrieval and embryo transfer are important: Women with high anticipatory state anxiety levels and high anticipatory cortisol concentrations have lower pregnancy rates. The influence of prolactin stress concentrations is unclear: Women with high prolactin concentrations seem to have more oocytes but lower fertilization rates.