The effect of maternal stress on blastocyst quality depends on maternal physiological status.

The effect of maternal stress on blastocyst quality, with respect to maternal metabolic status, was investigated in this study. We exposed female mice with different amounts of body fat to restraint stress and examined their blastocyst quality. Blood concentrations of corticosterone, leptin, adiponectin, insulin and glucose were measured in these females. Significantly lower stress-induced corticosterone elevations were observed in females with high and low amounts of body fat, indicating that the stress response was altered in these females. The basal leptin concentrations were significantly higher in females with high amounts of body fat than in females with low amounts of body fat, and stress induced different responses in these two groups of females. Our results showed that maternal stress can significantly increase the proportion of blastocysts that contain dead (apoptotic) cells in females with high and medium amounts of body fat. In females with low amounts of body fat, the proportion of blastocysts containing dead (apoptotic) cells was already increased before the stress exposure, and application of stress did not significantly change this parameter. Our results showed that the effects of maternal stress on early embryos can depend on the actual physiological status of the maternal organism exposed to stress.