Ovarian Reserves and Fertility | The Sleep and Infertility Study | Why Does Sleep Matter for Fertility?
Overview
Infertility is a growing concern in today's modern society. Many more people are seeking fertility treatments than ever.
Experts say it could be biological, environmental, and lifestyle factors. A study in Scientific Reports has added a new piece to the puzzle sleeplessness.
Fujian Medical University researchers found a link between sleep issues and lower ovarian reserve in women undergoing infertility treatments, showing a complex link between sleep and reproductive health.[1]
The study offers new insights into a pressing issue for many women worldwide.
Continue reading to learn more about this brilliant study!
Ovarian Reserves and Fertility
Clinicians use ovarian reserve to assess fertility in women seeking treatment, evaluating a person's ovarian reserve using tests. These include blood hormone tests (like FSH and LH) and ultrasounds (like antral follicle count).[2]
The results from these tests let fertility experts predict the outcome of assisted reproductive treatment, which include diminished ovarian reserves (DOR) that cause poor response to in vitro fertilization (IVF).
Diminished ovarian reserves (DOR) refers to a reduced number or quality of eggs in the ovaries. Women with DOR often produce fewer viable eggs, lowering their chances of pregnancy.[3]
Despite substantial investigation, the reasons for DOR remain poorly understood, necessitating further research into its potential causes, such as sleep problems.
The Sleep and Infertility Study
Experts have linked sleep problems to reduced fertility. A study at China's Fujian Provincial Maternity and Children's Hospital supports this finding.
The scientists enrolled 979 women in fertility treatment at the hospital from 2020 to 2021.[1]
They assessed the participants' sleep quality using self-reported tools, which included the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS).
Researchers also assessed the women's ovarian reserves with tests like the antral follicle count and hormone tests.
The participants were then split into two groups: those with decreased ovarian reserve (DOR group) and those with sufficient reserve (Non-DOR group).
One hundred forty-eight women were assigned to the DOR group, while 831 women were in the non-DOR group. Notably, the women in the DOR group (35 years) were significantly older than those with normal ovarian reserves (31 years).
For more analysis, the scientists further categorized the participants. They grouped them by sleep duration: less than 6 hours, 6 to 8 hours, and over 8 hours. They also considered how long it took them to fall asleep (Sleep onset latency).
The scientists then assessed the participants' sleep quality and ovarian reserve. The results were striking:
The DOR group had a shorter sleep onset delay. They averaged 15 minutes to fall asleep, while the non-DOR group took 22 minutes. However, the sleep duration for women in the DOR group (7.35 hours) was shorter than those with normal ovarian reserves (7.57 hours).
Participants who slept more than eight hours had higher anti-mullerian blood (AMH) levels and antral follicle counts than those who slept about six hours. (The AMH test can help evaluate ovarian function and reserve.)
Sleep onset latency also affected the AMH level and follicular count. Women with sleep onset latency between 30-44mins had the highest AMH levels. While those with a latency of 45 minutes or more in sleep onset had the highest antral follicle count.
Further analysis found that age, sleep latency, and PSQI scores were independent risk factors for DOR.
Snoring and PSQI-sleep delay were independent risk factors in patients aged 35 and older.
Also, when the participants were grouped by BMI, age was the only significant risk factor for DOR in women with a BMI over 25kg/m². In contrast, age and sleep latency were risk factors in women with a BMI of less than 25 kg/m².
The study's findings suggest that disrupted sleep may contribute to ovarian dysfunction, compounding the challenges faced by women with fertility issues.
Why Does Sleep Matter for Fertility?
Sleep disorders disrupt hormones that are vital for ovarian function, including the hypothalamic-pituitary-gonadal (HPG) axis.[4]
Poor sleep can also disrupt reproductive hormones, including follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH). Both are key indicators of ovarian reserve.
Also, snoring and sleep apnea can cause oxidative stress and inflammation.[5] These factors can speed up ovarian aging.[6]
Experts believe these stressors may disrupt the hormonal balance essential for egg development and ovulation.
The Study's Implication for Women Seeking Infertility Treatment
The researchers said their study highlights the need to improve sleep quality in women undergoing assisted reproductive technology (ART).
Simple measures, such as improving sleep hygiene or treating sleep problems, may improve ovarian function and increase the chances of a healthy pregnancy.[1]
Researchers also noted that incorporating sleep tests into infertility assessments may improve treatment and outcomes.
What's the Takeaway?
Sleep disturbances may cause infertility by reducing women's ovarian reserve. Better sleep may be key to becoming parents for women having trouble getting pregnant.
References:
1. Cai, X.-F., Wang, B.-Y., Zhao, J.-M., Nian, M.-X., Lin, Q.-C., & Huang, J.-F. (2024). Association of sleep disturbances with diminished ovarian reserve in women undergoing infertility treatment. Scientific Reports, 14(1), 1–8. https://doi.org/10.1038/s41598-024-78123-w
2. Ulrich, N. D., & Marsh, E. E. (2019). Ovarian Reserve Testing: A Review of the Options, Their Applications, and Their Limitations. Clinical obstetrics and gynecology, 62(2), 228–237. https://doi.org/10.1097/GRF.0000000000000445
3. Cohen, J., Chabbert-Buffet, N., & Darai, E. (2015). Diminished ovarian reserve, premature ovarian failure, poor ovarian responder--a plea for universal definitions. Journal of assisted reproduction and genetics, 32(12), 1709–1712. https://doi.org/10.1007/s10815-015-0595-y
4. Balbo, M., Leproult, R., & Van Cauter, E. (2010). Impact of sleep and its disturbances on hypothalamo-pituitary-adrenal axis activity. International journal of endocrinology, 2010, 759234. https://doi.org/10.1155/2010/759234
5. Sang, D., Lin, K., Yang, Y., Ran, G., Li, B., Chen, C., Li, Q., Ma, Y., Lu, L., Cui, X.-Y., Liu, Z., Lv, S.-Q., Luo, M., Liu, Q., Li, Y., & Zhang, E. E. (2023). Prolonged sleep deprivation induces a cytokine-storm-like syndrome in mammals. Cell, 186(25), 5500-5516.e21. https://doi.org/10.1016/j.cell.2023.10.025
6. Aiken, C. E., Tarry-Adkins, J. L., Spiroski, A. M., Nuzzo, A. M., Ashmore, T. J., Rolfo, A., Sutherland, M. J., Camm, E. J., Giussani, D. A., & Ozanne, S. E. (2019). Chronic gestational hypoxia accelerates ovarian aging and lowers ovarian reserve in next-generation adult rats. FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 33(6), 7758–7766. https://doi.org/10.1096/fj.201802772R
