Human fertility and sleep disturbances: A narrative review

The protective effect of bromelain on testicular dysfunction and oxidative stress induced by REM sleep deprivation in adult male rats

Male infertility is a significant global health concern, with sleep deprivation emerging as a potential contributing factor due to its impact on oxidative stress and reproductive function. This study investigates the protective effects of bromelain, a natural anti-inflammatory enzyme, on testicular dysfunction induced by Rapid eye movement (REM) sleep deprivation in adult male rats. Thirty-six rats were divided into control, REM sleep-deprived (REM-dep), and REM-deprived with bromelain treatment (REM-dep+Br) groups. REM sleep deprivation was induced for a 21-day period using the flower pot technique, with concurrent oral administration of bromelain (200 mg/kg) throughout this period. Finally, sperm parameters, testicular stereology, antioxidant markers (Nrf-2, γ-GCS, and GSH), and inflammatory/apoptotic markers (TNF-α, and Caspase-3) were evaluated across study groups. REM sleep deprivation significantly reduced sperm count, motility (total, and progressive), and normal morphology while increasing DNA fragmentation compared to control group. Testicular stereology revealed decreased spermatogenic cells, Sertoli cells, Leydig cells, and Johnsen scores. Bromelain administration significantly improved total sperm motility, increased spermatid numbers, and restored Leydig cell counts compared to REM-dep group. Antioxidant markers (Nrf-2, γ-GCS, GSH) were significantly reduced in the REM-dep group but restored with bromelain treatment. Immunohistochemistry showed elevated TNF-α and Caspase-3 expression in the REM-dep group, which was mitigated by bromelain administration. These findings suggest that REM sleep deprivation induces testicular dysfunction through oxidative stress and inflammation, while bromelain exerts protective effects via its antioxidant and anti-inflammatory properties. This study highlights bromelain as a potential protective /therapeutic agent for mitigating sleep deprivation-induced male reproductive dysfunction.

Study on the association between night shift work and reproductive functions among male workers: a systematic review and meta-analysis

BACKGROUND

There has been growing interest to study impact of night shift work on male reproductive health, which is regulated by the hypothalamic-pituitary-gonadal axis and influenced by circadian rhythms. This systematic review and meta-analysis aim to explore the association between night shift work and male reproductive health outcomes.

METHODS

This systematic review and meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines (PROSPERO: CRD42022379770). Studies comparing male reproductive parameters [e.g., semen profile, testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH)] between night shift workers and non-shift workers were systematically searched in PubMed, Scopus and EMBASE databases. Heterogeneity (I2 and Cochran-Q test), risk of bias (Newcastle-Ottawa Scale and funnel plots), sensitivity analyses were performed when applicable.

RESULTS

Eight studies were included in this review from 6397 citations screened. The pooled mean difference in sperm count was -18.38 × 106 sperm (-59.82 to 23.07; n = 3, I2 = 85.12%) and serum testosterone was 15 ng/dL (-19.3 to 49.39; n = 5, I2 = 63%), indicating that shift workers had lower sperm counts but marginally higher serum testosterone levels compared to controls. The majority of included studies exhibited a high risk of bias in participant selection, group comparability and exposure assessment.

CONCLUSION

The analysis highlights the potential impact of night shift work on sperm parameters and hormone levels. Future research with standardized methods and larger samples is needed to better understand the circadian disruption's effects, informing healthcare practices and policies for male reproductive health.

The Association Between Sleep Disorder and Female Infertility: A Mediation Analysis of Inflammatory and Oxidative Markers

Background: Sleep disorder in women of reproductive age may contribute to infertility development, but there is a lack of substantial evidence linking sleep disorder to inflammation and oxidative stress, and the subsequent risk of infertility. Methods: A total of 2365 women aged 18-45 years from the National Health and Nutrition Examination Survey (NHANES) were included in this analysis. Sleep disorder and infertility were assessed according to NHANES questionnaire data module. Inflammatory and oxidative biomarkers such as high-sensitivity C-reactive protein (hs-CRP), white blood cell (WBC), gamma-glutamyl transpeptidase (GGT), albumin, ferritin, and total bilirubin were derived from the laboratory data module, and systemic immune inflammation index (SII), and system inflammation response index (SIRI) were calculated based on complete blood cell counts. A sophisticated multistage sampling design and weighted multivariable adjusted regression models were employed to conduct comprehensive analysis. Mediation models were applied to explicate the mediating role of biomarkers of inflammation and oxidative stress. Results: Compared to the noninfertility group, the infertile participants had a higher incidence of sleep disorder (34% vs. 25%, p < 0.05). In models with fully adjusted covariates, sleep disorder was positively associated with infertility risk (OR: 1.58; 95%CI: 1.01-2.50, p < 0.05), particularly in subgroups of individuals aged over 30 years old (OR: 1.75; 95%CI: 1.00-3.04, p < 0.05) or with a body mass index (BMI) ≥ 30 kg/m2 (OR:2.05; 95%CI: 1.00-4.22, p < 0.05). In terms of mechanisms, there were significant correlations between inflammatory and oxidative markers and both sleep disorder and infertility. Mediation analysis indicated that hs-CRP, SII, SIRI, GGT, and total bilirubin played a significant mediating role in the relationship between sleep disorder and infertility, accounting for 0.4822%, 6.0515%, 1.2485%, 5.1584%, and 0.4738%, respectively. Conclusions: Sleep disorder is a significant risk factor for infertility, particularly in women aged >30 years or with obesity. Furthermore, the presence of inflammation and oxidative stress status in the body, which also significantly mediate the association between sleep disorder and infertility, can be swiftly and repeatedly identified through blood tests. Sleep, as a modifiable behavioral pattern, can be regarded as a new strategy to cope with infertility.

Effect of solution focused approach on women aged 35 or over with in vitro fertilization-embryo transfer: A quasi-experimental trial

BACKGROUND

We aimed to explore the influence of solution-focused approach (SFA) on anxiety and depression, sleep quality, quality of life and clinical pregnancy rate among women aged 35 or over undergoing in vitro fertilization-embryo transfer (IVF-ET).

METHODS

The study was performed at the reproductive center in a public hospital in Lanzhou city. Totally, 112 women were enrolled in this study, and were divided into group SFA (n = 56) and group control (n = 56). The patients in the group SFA completed five sessions (30 minutes/turn), and patients in the group control received routine care.

RESULTS

The intervention group showed a significant decrease in anxiety (t =  11.906, P <  0.001) and depression scores (t =  14.991, P <  0.001), as well as PSQI scores (t =  7.055, P <  0.001), and increased FertiQoL scores (t =  -2.828, P <  0.001). Comparing the two groups after the intervention, the intervention group demonstrated significantly lower SAS scores (t =  -10.348, P <  0.001), SDS scores (t =  -8.416, P <  0.001), and PSQI scores (t =  -5.087, P <  0.001), while FertiQoL scores were higher than the control group (t =  2.389, P =  0.019). The intervention group reported a satisfaction rate of 96.2% to 100% with the SFA.

CONCLUSIONS

SFA can help relieve anxiety and depression, improve sleep quality and reproductive life quality. Improvement in psychological distress might not contribute to increasing female fecundity. Patients in the group SFA were satisfied with the intervention.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2300075444).

Relationship Between Sleep Disturbances and In Vitro Fertilization Outcomes in Infertile Women: A Systematic Review and Meta-Analysis

BACKGROUND

In vitro fertilization (IVF) has been acknowledged as the primary assisted reproductive technique for fertilizing oocytes outside the female reproductive system. Sleep disorders are likely to affect infertility and its treatment. The present study was to investigate the relationship between sleep disturbances and IVF outcomes in infertile women.

METHODS

Databases, including PubMed, Embase, Cochrane Library, ProQuest, and Web of Science, were searched for the relevant articles published up to September 2023. The Newcastle-Ottawa Scale was used to assess the methodological quality of the included studies. Moreover, the random and fixed effects models using the STATA (v.11) software program presented the odds ratio with a 95% confidence interval (CI). Ultimately, a funnel plot was recruited to examine the sensitivity analysis.

RESULTS

During the initial search, 426 articles were retrieved, and ultimately, nine studies remained for systematic review, and among them, four studies entered into the meta-analysis (two cohort and two cross-sectional studies). According to the fixed effects model of the cross-sectional studies, the association between sleep quality and pregnancy rate was not confirmed (OR = 0.94; 95% CI = 0.81-1.07). Regarding the fixed effects model of included cohort studies, the results indicated an association between sleep quality and the pregnancy rate (OR = 1.08; 95% CI = 1.03-1.14). According to the random effects model of the cross-sectional studies, there was no significant association between sleep quality and pregnancy rate (OR = 0.82; 95% CI = 0.37-1.26). Regarding the random effect analysis of included cohort studies, the results indicated an association between sleep quality and the pregnancy rate (OR = 1.08; 95% CI = 1.03-1.14). Based on the total fixed effect analysis of the cross-sectional and cohort studies, the results also showed a significant association between sleep quality and pregnancy rate among infertile women (OR = 1.06; 95% CI = 1.01-1.11). In contrast, according to the random effect of the total studies, this association was not confirmed (OR = 1.02; 95% CI = 0.90-1.14).

CONCLUSION

Although the meta-analysis of the cohort studies showed a significant association between sleep quality and IVF outcomes, such as pregnancy rate, due to the novelty of the subject, more studies have not been published, and this study is considered a preliminary meta-analysis. Therefore, more studies with a strong methodology need to assess the relationship between sleep disorders and IVF outcomes.

[The effect of sleep and other medical and social factors on a woman's reproductive function]

According to the World Health Organization, infertility affects one in six couples worldwide, highlighting the relevance of strategies to preserve women's reproductive health. In this review, we consider the impact of various medical and social factors, such as sleep quality, anxiety, depression, lifestyle, level of education, income, etc., on fertility. Particular attention is paid to the modifiability of these factors, which opens up additional opportunities for preventing and treating infertility. The association between the adjustment of medical and social factors and improved outcomes of assisted reproductive technologies, such as in vitro fertilization, is emphasized. Attention to medical and social factors and their adjustment is an important direction for improving fertility and the success of infertility prevention and treatment, and further research and implementation in clinical practice are also required.

Sleep disturbances and female infertility: a systematic review

BACKGROUND

Sleep disturbances are more prevalent among women with infertility. Current research increasingly highlights the significant relationship between sleep disturbances and female infertility, suggesting that sleep may be a key factor in reproductive health. In this review, we aim to delve into the complex interplay between sleep disturbances and female infertility, as well as to assess the underlying mechanisms involved, and seek to illuminate the causes of sleep-related fertility issues. The understanding of these contents may help clinicians enhance clinical strategies for managing sleep disturbances in women facing infertility challenges and provide timely support to those seeking fertility treatments.

METHODS

A comprehensive literature search was conducted in the PubMed and EMBASE databases. Studies that described sleep patterns or any type of sleep disturbance, sleep breathing disorders and their associations with female infertility or female fecundity, published between January 1, 2010, and November 1, 2023, were identified and extracted. The screening, data extraction, and quality assessment processes were independently performed by paired reviewers. The quality of the included studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal tools for observational and cohort studies.

RESULTS

A total of 1,179 articles were initially identified from the search strategy (PubMed, n = 377; EMBASE, n = 802). After removing duplicates (n = 83) and screening for eligibility (n = 75), 19 studies were reviewed and determined to be eligible for inclusion. Infertile women generally report poorer sleep quality and exhibit more evening sleep chronotypes. Sleep disorders are significantly associated with infertility. Poor sleep quality, extreme sleep durations, and certain sleep chronotypes are associated with poorer fertility treatment outcomes, such as a reduced number of retrieved oocytes, decreased embryo quality, and lower fertilization rates. Obstructive sleep apnea (OSA) is also more prevalent in women with fertility issues, especially those with polycystic ovary syndrome (PCOS), and may negatively impact reproductive outcomes. The circadian rhythms of the Clock gene system, melatonin and hormone dysregulation, oxidative stress and immune response are considered to be potential mechanisms explaining how sleep disturbance impairs reproductive function, remain to be fully elucidated, and therefore, require further investigation.

CONCLUSIONS

Sleep disturbances are negatively associated with female infertility and poor fertility treatment outcomes. Longitudinal studies are expected to substantiate these findings and inform more nuanced approaches to prior sleep management and lifestyle advisement for infertile women, especially those undergoing fertility treatments.

TRIAL REGISTRATION

This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO, #CRD42024498443).

Sleep quality, perceived stress and associated factors in women undergoing IVF treatment: short-term longitudinal study

BACKGROUND

Despite limited studies in the literature, it is hypothesised that lifestyle factors are modifiable habits that have an impact on couples' fertility health. However, the relationship between sleep quality and infertility is an area that needs to be clarified.

OBJECTIVE

To determine sleep quality and associated factors in women receiving in vitro fertilisation treatment and to evaluate the changes in sleep over the treatment cycle.

METHODS

This is a longitudinal descriptive study conducted on 158 women in two infertility centres in Izmir, Turkey. Data were collected using the Personal Introduction Form, Pittsburgh Sleep Quality Index, Visual Analogue Stress Scale, and Physical Symptoms List. Data were collected during three different treatment periods: beginning of the in vitro fertilisation trial, oocyte pick-up day and the postembryo transfer period.

RESULTS

The sleep quality score of women progressively decreased as treatment progressed (p < .001). A strong positive correlation was determined between stress and sleep quality (p < .001). Additionally, advanced age, low education level, shift work, prolonged treatment and economic distress were associated with poorer sleep quality (p < .001). In addition, breast fullness, abdominal distension, and pain (p < .001) observed until the oocyte pick-up day, as well as nausea and fatigue during the postembryo transfer period (p < .001), were identified as physical symptoms affecting sleep quality.

CONCLUSION

This article provides information on sleep quality during in vitro fertilisation and guides healthcare professionals to encourage and improve women's sleep quality.

The mediating and moderating effects of resilience on the relationship between sleep quality and psychological distress in Chinese women with infertility

BACKGROUND

Research has widely indicated that the psychological distress experienced by infertile patients during fertility treatments may have a negative effect on the results of assisted reproduction. Although numerous studies have shown that psychological resilience and sleep quality are important influencing factors for psychological distress, the mediating mechanisms of psychological resilience in the relationship between sleep quality and psychological distress for Chinese women in particular remain unclear. Therefore, the current study investigates the association between sleep quality, resilience, and psychological distress in Chinese women with infertility and examines the mediating and moderating roles of resilience on the relationship between sleep quality and psychological distress.

METHODS

In this cross-sectional study, a total of 595 women with infertility who were undergoing IVF-ET were recruited at the Reproductive Medicine, Shandong University, from April to November 2019. Participants were instructed to complete four questionnaires, including a questionnaire about socio-demographic and clinical-related information, the Pittsburgh Sleep Quality Index (PSQI), the 10-item Connor-Davidson Resilience Scale (CD-RISC-10), and the Kessler-10 (K10). Pearson's correlation analysis was conducted preliminarily to describe the relationships between sleep quality, resilience, and psychological distress. A mediation model and a moderated model were constructed and analyzed using the PROCESS macro for SPSS. The Johnson-Neyman (J-N) technique was then used to identify the regions of significance across the levels of moderator values.

RESULTS

Patients in the sample had a high prevalence of psychological distress (48.6%, K10 scores > 22), and mediation analysis indicated that resilience played a partially mediating role in the relationship between sleep quality and psychological distress (indict effect = 0.072, P < 0.001). Moderation analysis indicated that resilience also moderated the association between sleep quality and psychological distress.

CONCLUSIONS

Resilience may play a key role in the relationship between sleep quality and psychological distress. Our findings imply that resilience training may therefore be an effective component of psychological distress intervention in women with infertility.

Antibiotic exposure associated with nighttime sleep duration and daytime sleepiness in newlyweds

Few studies have explored the relationship between antibiotic exposure and sleep in newlyweds. We applied the actor-partner interdependence moderation model to estimate the relationships of antibiotic exposure with nighttime sleep duration (weekday, weekend, and average sleep durations) and daytime sleepiness in newlyweds. We found that 99.0% of the 2698 enrolled individuals were exposed to at least one antibiotic. Among the newlyweds, exposure to florfenicol (β, - 0.077; 95% confidence interval [CI], - 0.143, - 0.011), exposure to chloramphenicols (- 0.086 [- 0.160, - 0.011]), and exposure to veterinary antibiotics (VAs) (- 0.106 [- 0.201, - 0.010]) were negatively associated with weekday sleep duration. Florfenicol, chloramphenicols, and VAs were also inversely related to average sleep duration in the newlyweds. Ciprofloxacin and cyadox exposure was significantly associated with an increase of 0.264 (0.030, 0.497) and (0.375 [0.088, 0.663]) Epworth Sleepiness Scale (ESS) scores in the newlyweds, respectively. Gender moderated the actor-partner effects of erythromycin and tetracyclines on the newlyweds' weekday sleep duration and ESS scores. Overall, exposure to florfenicol, chloramphenicols, and VAs shortened weekday and average sleep durations of newlyweds. Exposure to ciprofloxacin and cyadox promoted daytime sleepiness. Gender moderated the actor-partner effects of specific antibiotics on the weekday sleep duration and ESS scores of the newlyweds.

Microbiota Composition and Probiotics Supplementations on Sleep Quality-A Systematic Review and Meta-Analysis

The gut microbiota (GM) plays a crucial role in human health. The bidirectional interaction between GM and the central nervous system may occur via the microbiota-gut-brain axis, possibly regulating the sleep/wake cycle. Recent reports highlight associations between intestinal dysbiosis and sleep disorders, suggesting that probiotics could ameliorate this condition. However, data are poor and inconsistent. The aim of this quantitative metanalytic study is to assess the GM composition in sleep disturbances and evaluate probiotics' effectiveness for managing sleep disorders. A systematic review was carried out until July 2022 in online databases, limiting the literature research to human studies and English language articles. No significant GM diversity between patients with sleep disturbances versus healthy controls was found, revealed by α-diversity, while β-diversity is missing due to lack of proper reporting. However, probiotics supplementation significantly reduced the self-assessed parameter of sleep quality and disturbances Pittsburgh Sleep Quality Index (PSQI) score compared with the placebo. No difference in the Epworth Sleepiness Scale (ESS) score was found. While available data suggest that GM diversity is not related to sleep disturbances, probiotics administration strongly improves sleep quality as a subjective perception. However, heterogeneity of data reporting in the scientific literature should be considered as a limitation.

A bibliometric analysis of the application of imaging in sleep in neurodegenerative disease

Objective

The purpose of this study was to examine the current state of the application of imaging in sleep research in degenerative disease, as well as hotspots and trends.

Materials and methods

A search was conducted on the Web of Science Core Collection (WoSCC) between 1 September 2012, and 31 August 2022 for literature related to sleep imaging. This study analyzed 7,679 articles published in this field over the past 10 years, using CiteSpace to analyze tendencies, countries, institutions, authors, and hotspots.

Results

There were 7,679 articles on the application of imaging to sleep research published by 566 institutions located in 135 countries in 1,428 journals; the number of articles was increasing on a yearly basis. According to keyword analysis, the research direction of the application of imaging in sleep research focused on the effects of degenerative diseases on sleep, such as Parkinson's disease, Alzheimer's disease, and small vessel disease. A literature evaluation found that Parkinson's disease, insomnia, sleep quality, and rapid eye movement sleep behavior disorder were the top research trends in this field.

Conclusion

A growing body of research has focused on sleep disorders caused by degenerative diseases. In the application of imaging to sleep research, magnetic resonance functional brain imaging represents a reliable research method. In the future, more aging-related diseases may be the subject of sleep-related research, and imaging could provide convenient and reliable evidence in this respect.