Sleep and Female Fertility
Does Sleep Affect Female Fertility?
We all know the consequences of one (or more!) nights of poor sleep: days where you feel you just can’t focus or maybe that your emotions are barely contained. In extreme cases, you might even catch yourself drifting off to sleep when sitting still for too long. However, what is less well-understood is whether or not a lack of good quality sleep has any effect on a woman’s ability to become pregnant. This is what we want explore further here.
What we know so far:
To date, the majority of research looking at this topic has involved women whose jobs require them to work shifts (i.e. working a night shift or a late afternoon shift), such as nurses or flight attendants. Furthermore, this research focuses primarily on the effects such work has on menstrual patterns, and not as much on pregnancy-related outcomes. For example, researchers have measured whether women who work night shifts for a certain period of time are more likely to have an increased cycle length, rather than whether or not they are more or less likely to become pregnant. So, for that reason, we don’t currently have a very clear answer as to if or how sleep affects female fertility.
Regardless of the limitations of the research, we can confidently say that women who work shifts experience disruptions in their menstrual cycle in response to their erratic sleep schedule. (1–3) Whether or not these changes in menses translate into changes in female fertility is less well-understood. Some of this same research suggests that there are no significant differences between the rates of infertility amongst women who work shift work versus those who don’t. (1–3) However, the authors of these articles do acknowledge that shift work may in fact have an effect on general fertility, as well as increased rates of early, spontaneous pregnancy loss, which their findings suggest are increased in women who perform shift work. (1,2)
What does newer evidence suggest?
Indeed, there are plausible reasons as to why changes in sleep would have an impact on female fertility. One narrative review conducted in 2014 provides multiple explanations as to how this might be. In the article, the authors explain multiple means by which sleep may affect female fertility. At the top of the list is stress. According to the authors, stress may play a key role in mediating female fertility (4). Sleep and stress often have what’s described as a reciprocal relationship. Meaning, when a person becomes stressed, his or her quality of sleep is likely to suffer, and, due to that lack of sleep, that person’s ability to cope with stress becomes compromised. In addition to this indirect effect, the authors also posit that sleep itself may have its own direct effect on fertility, which only adds to the potentially harmful effects imposed by stress. (4)
An observational study conducted in late 2017 adds credence to the argument that sleep affects female fertility. The authors of the study compared women between the ages of 20-45 who were diagnosed with a sleep disorder that was not due to obstructive sleep apnea, and compared them to other women who did not have the same issues with sleep. After 10 years of follow-up, their results suggested that women with sleep disorders were significantly more likely to develop infertility—as much as 5 times as likely, in women between the ages of 26 and 30. (5) As compelling as this information is, it is important to recognize that the results only demonstrate correlation and not causation. Meaning, there may very likely be other factors contributing to the observed results. Nonetheless, the authors’ conclusion that women with sleep disorders not related to sleep apnea are at increased risk of developing female infertility is highly plausible.
One last factor to consider is the hormone melatonin. Primarily responsible for regulating our circadian rhythm—our sleep-wake cycle—melatonin has been implicated as an underlying instigator in sleep disorders. (6) If we again consider shift workers, it is believed that melatonin plays a key role in the sleep disturbances that these individuals often experience. (1–3) For this reason, it is believed that melatonin may also play a part in a female shift worker’s ability to become pregnant. More broadly, melatonin has also been studied for its role in general female fertility, but with mixed results. (4)
What does this information really mean?
It can be difficult to parse through all the information and extract a takeaway message. In this case, the message is that we don’t have a definitive answer as to how or to what degree sleep affects female fertility, but it seems likely that it can. In addition to the mechanisms briefly discussed in this post, there are many others that provide even more reason to consider sleep an important mediator of female fertility. Since sleep is important for many reasons other than just becoming pregnant, it makes sense to give yourself enough time to sleep each night. Doing so will make for a healthier, happier you.
Bottom line
Sleep is important for so many aspects of our lives. In light of the current research on the topic, prioritize good quality sleep, especially when trying to get pregnant.
Be sure to follow these good sleep hygiene tips to ensure you’re getting good quality sleep on a regular basis
Although not currently considered necessary by many, if possible, consider avoiding shift work that requires alternation between day and night shifts.
The most important sleep tip: wake up at the same time everyday. This will regulate sleep patterns for most people.
References:
1. Stocker LJ, Macklon NS, Cheong YC, Bewley SJ. Influence of shift work on early reproductive outcomes: a systematic review and meta-analysis. Obstet Gynecol. 2014;124(1):99-110. doi:10.1097/AOG.0000000000000321
2. Lawson CC, Whelan EA, Lividoti Hibert EN, Spiegelman D, Schernhammer ES, Rich-Edwards JW. Rotating shift work and menstrual cycle characteristics. Epidemiol Camb Mass. 2011;22(3):305-312. doi:10.1097/EDE.0b013e3182130016
3. Labyak S, Lava S, Turek F, Zee P. Effects of shiftwork on sleep and menstrual function in nurses. Health Care Women Int. 2002;23(6-7):703-714. doi:10.1080/07399330290107449
4. Kloss JD, Perlis M, Zamzow J, Culnan E, Gracia C. Sleep, Sleep Disturbance and Fertility in Women. Sleep Med Rev. 2015;22:78-87. doi:10.1016/j.smrv.2014.10.005
5. Wang I-D, Liu Y-L, Peng C-K, et al. Non-Apnea Sleep Disorder Increases the Risk of Subsequent Female Infertility—A Nationwide Population-Based Cohort Study. Sleep. 2018;41(1). doi:10.1093/sleep/zsx186
6. Costello RB, Lentino CV, Boyd CC, et al. The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature. Nutr J. 2014;13. doi:10.1186/1475-2891-13-106
7. Lauria L, Ballard TJ, Caldora M, Mazzanti C, Verdecchia A. Reproductive disorders and pregnancy outcomes among female flight attendants. Aviat Space Environ Med. 2006;77(5):533-539.