New study links shorter time to fall asleep and snoring to higher risk of ovarian decline

By Vijay Kumar MalesuReviewed by Danielle Ellis, B.Sc.Nov 5 2024

The findings suggest that sleep disturbances may impact hormone levels and follicular development. 

In a recent study published in the Scientific Reports, a group of researchers investigated the association between sleep parameters and diminished ovarian reserve (DOR) in women seeking infertility treatment at a clinic.

Background 

Reproduction has shown remarkable conservation over time. Recently, surveys indicate a rising trend of infertility among younger women, driven by factors such as environmental pollution,  industrialization, societal pressures, and various health conditions.

Ovarian reserve is a key marker for assessing female fertility. Clinicians evaluate ovarian reserve through biochemical tests (like follicle-stimulating hormone (FSH), luteinizing hormone (LH), and antimüllerian hormone (AMH)) and ultrasound methods (such as antral follicle count).

DOR has become a significant factor in assisted reproductive technology (ART) procedures, often resulting in poor response during in vitro fertilization (IVF). Despite extensive research, the causes of DOR are still poorly understood, necessitating further research into its potential links to sleep disorders.

About the study

Couples seeking infertility treatment at the Center of Reproductive Medicine, Fujian Provincial Maternity and Children’s Hospital, affiliated with Fujian Medical University, were included in this study from July 2020 to June 2021. Data were collected from male participants who underwent either IVF or intracytoplasmic sperm injection (ICSI) at the clinic.

Inclusion criteria required couples to be scheduled for IVF or ICSI, while exclusion criteria included pregnancy or lactation, hypothalamic-pituitary disorders, history of ovarian surgery, concurrent illnesses causing insomnia, prior treatment for sleep disorders, and diagnosed conditions affecting the urogenital system. Written informed consent was obtained from all participants, and the study protocols received ethical approval from the hospital’s ethics committee.

Participants were categorized into two groups according to their ovarian reserve status: DOR and non-DOR. Diagnosis of DOR required meeting at least two specific criteria related to hormone levels and follicle count. Hormone levels were assessed using the Chemiluminescence method, and ovarian follicle distribution was calculated through color ultrasound.

Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI), the STOP-Bang Questionnaire for obstructive sleep apnea, and the Epworth Sleepiness Scale (ESS) for daytime sleepiness. Data analysis was conducted using IBM-SPSS version 22.0, applying appropriate statistical tests to identify significant differences and risk factors for DOR.

Study results 

A total of 979 women were enrolled in the study, with 148 diagnosed with DOR and a mean age of 35.35 years. The remaining 831 women, classified as the non-DOR group, had a mean age of 31.70 years, showing a statistically significant difference (p < 0.001). Notable differences were also observed between the groups in key hormonal and follicular characteristics, including follicle count, AMH, FSH, estradiol (E2), and testosterone (T), all with p-values below 0.001.

The PSQI, ESS, and STOP-Bang Questionnaire were employed to assess sleep quality. The results indicated that the DOR group had significantly shorter sleep onset latency, averaging 15 minutes compared to 22 minutes in the non-DOR group (p = 0.001). Additionally, total sleep duration was lower in the DOR group, with an average of 7.35 hours compared to 7.57 hours in the non-DOR group (p = 0.014). While the PSQI revealed significant differences in sleep onset latency and sleep duration, there were no notable differences in the ESS and STOP-Bang scores between the groups.

Further analysis categorized total sleep duration into three groups: greater than 8 hours, 6 to 8 hours, and 6 hours or less, while sleep onset latency was divided into three categories: less than 30 minutes, 30 to 44 minutes, and 45 minutes or more. Significant differences were observed in AMH and follicle counts based on sleep duration, with higher levels recorded in those who slept more than 8 hours compared to those who slept 6 hours or less (p = 0.007, 0.005, 0.030, respectively).

Sleep onset latency also influenced AMH levels, with the 30 to 44-minute group showing significantly higher AMH levels compared to the others (p = 0.001, 0.011, 0.036). The group with a sleep onset latency of 45 minutes or more exhibited higher follicle counts than those in shorter latency categories.

Logistic regression analysis revealed that age, sleep latency from the PSQI, and overall PSQI scores were independent risk factors for DOR, with adjusted odds ratios of 0.831, 1.708, and 0.870, respectively (p < 0.001, 0.002, 0.036). Among subjects aged 35 years and older, snoring and PSQI-sleep latency were identified as independent risk factors (OR = 2.489, 2.007; p = 0.040, 0.008). Additionally, when stratified by body mass index (BMI), only age was a significant risk factor for DOR in the BMI ≥ 25 kg/m² group (OR = 0.822; p < 0.001), whereas both age and sleep latency were risk factors in the BMI < 25 kg/m² group (OR = 0.828, 1.761; p < 0.001, 0.003).

Conclusions 

To summarize, the study found that shorter sleep onset latency and snoring significantly increased DOR risk, especially in women aged 35 and older. The findings highlight DOR as a growing challenge for women seeking pregnancy, with sleep disturbances potentially impairing hormone secretion and follicular development. Integrating sleep assessments into infertility evaluations could improve reproductive outcomes, particularly for women over 35.