<b><i>Introduction:</i></b> A firm consensus on the effectiveness of psychological interventions during infertility treatment has not been reached yet in terms of mental health and pregnancy rates. Moreover, the influence of these interventions on embryo cleavage kinetics has not been investigated. <b><i>Objective:</i></b> The aim of this work was to study whether stress management in couples undergoing an intracytoplasmic sperm injection (ICSI) cycle influences stress levels, mitochondrial DNA (mtDNA) levels in granulosa cells, and cleavage-stage embryos. <b><i>Methods:</i></b> Infertile couples were randomized into a treatment as usual (TAU) group (<i>n</i> = 30) and stress management program (SMP) group (<i>n</i> = 29) at the beginning of an ICSI cycle. Couples in the SMP group attended education and relaxation sessions at each visit to the clinic for folliculometry. The perceived stress scale (PSS) was used to assess stress levels at the beginning and end of the cycle. Moreover, mtDNA levels of granulosa cells and embryo morphokinetics were evaluated. <b><i>Results:</i></b> Post-intervention, women in the SMP group had significantly lower PSS scores than their initial PSS (<i>p</i> &#x3c; 0.001; effect size, ES = 0.5) and than the final PSS of the TAU group (<i>p</i> = 0.02; ES = 0.09). Additionally, mtDNA levels were significantly lower in luteal granulosa cells of the SMP group than the TAU group (<i>p</i> = 0.02). An earlier time of pronuclei appearance (<i>p</i> = 0.03) and time to 2 cells (<i>p</i> = 0.015) and a faster time to full compaction (<i>p</i> = 0.045) were detected in the embryos of the SMP group compared with the TAU group. <b><i>Conclusion(s):</i></b> The implemented program may reduce stress levels, retard first embryo cleavage, and accelerate embryo compaction. Further studies with an active control group are needed to confirm these results.

No abstract