Recent advances on effects of sleep quality, duration, and circadian rhythm disruption on <italic>in vitro</italic> fertilization–embryo transfer outcomes

fertilization and embryo transfer (IVF-ET), the clinical pregnancy rate per oocyte retrieval cycle remains approximately 25%, making the identification of modifiable factors to improve success rates remains a clinical priority. Sleep disorders are highly prevalent among IVF-ET patients and their partners, with reported rates up to 91.1%, representing a substantial but often overlooked risk factor for IVF-ET outcomes. This review systematically examines the impact of sleep quality, sleep duration, and circadian rhythm on IVF-ET outcomes and discusses the underlying biological mechanisms. Current evidence indicates a significant positive correlation between sleep quality and pregnancy outcomes; women with good sleep quality have a 12% higher probability of live birth, whereas poor sleep quality is an independent risk factor for pregnancy failure in females and for reduced semen quality in males. The relationship between sleep duration and reproductive outcomes follows a non-linear inverted U-shaped pattern, with 7-8 hours identified as the optimal range. Deviations from this range-particularly sleep deprivation-are primarily associated with lower oocyte yield and reduced oocyte maturity. Moreover, circadian misalignment impairs embryo implantation rates and sperm motility by disrupting clock gene expression. Mechanistically, these sleep disturbances compromise gamete quality and endometrial receptivity through three major pathways: disruption of the hypothalamic-pituitary-gonadal axis homeostasis, induction of oxidative stress and inflammation, and interference with the normal rhythmic secretion of reproductive hormones. Intervention studies show that both pharmacological and non-pharmacological approaches can improve sleep, but their effects on IVF-ET outcomes vary. Melatonin may enhance embryo quality and pregnancy outcomes via antioxidant activity; behavioral interventions have been shown to increase live birth rates; and acupuncture may improve clinical pregnancy rates. Psychological and behavioral interventions can ameliorate sleep and emotional status, yet their direct benefit on pregnancy outcomes remains uncertain. In males, regular sleep schedules combined with antioxidant therapy may improve sperm quality. In conclusion, this review consolidates the evidence linking sleep quality, duration, and circadian rhythm to IVF-ET outcomes and their biological bases. Optimizing sleep patterns represents an important and modifiable strategy to improve IVF-ET success. Incorporating sleep health management throughout the entire IVF-ET treatment cycle may offer a low-cost, non-invasive adjunct to enhance pregnancy outcomes.