Impact of sleep characteristics on IVF/ICSI outcomes: A prospective cohort study

Infertility affects millions of individuals worldwide, imposing significant personal and societal burdens. Assisted reproductive technologies (ART), such as IVF and ICSI, provide hope for many, yet clinical pregnancy rate per embryo transfer remains around 35 %. Modifiable lifestyle factors, including sleep, may influence ART outcomes. However, the relationship between specific sleep characteristics and IVF/ICSI success is unclear. This study aims to explore the associations between sleep characteristics and various IVF/ICSI outcomes. Additionally, we investigated if perceived stress mediates these relationships.

This prospective cohort study enrolled 174 women undergoing IVF/ICSI at Zhongnan Hospital of Wuhan University from December 2021 to December 2023. Prior to initial ART treatment, participants completed the Pittsburgh Sleep Quality Index (PSQI) and the Perceived Stress Scale (PSS-10). IVF/ICSI outcomes such as the number of retrieved oocytes, matured oocytes, number of fertilized oocytes, fertilization rate, good-quality embryos, blastocyst formation rate and early pregnancy outcome (implantation and clinical pregnancy) were obtained from medical records. We employed multivariate generalized linear models to assess the associations between sleep characteristics and IVF/ICSI outcomes. Dose-response relationships between napping duration and maturation rate were analyzed using generalized additive models. Mediation analysis was used to assess the role of stress in the relationship between sleep characteristics and IVF/ICSI outcomes.

Women reporting poor sleep quality had significantly fewer retrieved oocytes (-22.89 %, 95%CI: 37.82 %, -4.00 %) and matured oocytes (-22.01 %, 95%CI: 37.54 %, -2.62 %). Those sleeping ≥10 h per night had fewer retrieved oocytes (-30.68 %, 95%CI: 48.88 %, -6.00 %), matured oocytes (-27.17 %, 95%CI: 46.57 %, -0.73 %), and good-quality embryos (-45.64 %, 95%CI: 65.43 %, -14.51 %). Women experiencing difficulty falling asleep more than three times a week had a significant reduction in blastocyst rates (-64.40 %, 95 % CI: 85.55 %, -12.30 %). Those reporting difficulty falling asleep less than once a week had fewer retrieved oocytes (-28.89 %, 95%CI: 47.34 %, -3.98 %), and matured oocytes (-27.77 %, 95%CI: 46.90 %, -1.73 %). Napping exceeding 1 h daily was associated with a significantly lower oocyte maturation rate (-73.8 %, 95%CI: 88.91 %, -38.06 %). A significant non-linear dose-response relationship was observed between napping duration and maturation rate (p < 0.001), with maturation rates initially increasing slightly with short naps but declining significantly with longer naps, particularly beyond 1 h. This relationship was significant among women with good sleep quality (PSQI ≤5) (p < 0.001) and those with normal BMI (p = 0.0005). Perceived stress did not significantly mediate these associations.

Our findings suggest that sleep characteristics, particularly poor quality, difficulty falling asleep, long sleep durations, negatively impact various IVF/ICSI outcomes. Longer daytime napping is inversely associated with oocyte maturation rates, especially among women with good sleep quality and normal BMI. Perceived stress did not appear to influence the relationship between sleep and IVF outcome. While optimizing sleep patterns may hold promise for improving IVF/ICSI success rates, it is essential to approach lifestyle guidance with caution, given the current limitations in confirming causative roles. Further studies are needed to clarify the extent and nature of the relationship between sleep characteristics and IVF/ICSI outcomes.