Short answer: Sleep appears to be linked to fertility, but the evidence is limited and causal relationships are unclear. Research suggests that both very short and very long sleep, as well as shift work and disrupted circadian rhythm, can be linked to irregular periods and poorer reproductive outcomes. Regular sleep times and seven to nine hours of sleep are reasonable benchmarks – but sleep alone does not determine whether you get pregnant.
Why sleep and hormones are connected
During sleep, the body switches from activity to recovery. According to 1177 Vårdguiden, communication between the cells that control the nervous system, hormonal system, and immune system increases when you sleep, while blood pressure, heart rate, and body temperature decrease. Since the menstrual cycle is regulated by a finely tuned interplay between the brain and the ovaries, it is biologically reasonable that circadian rhythm and sleep can play a role.
However, it is important to distinguish between mechanism and evidence. That sleep affects the hormonal system is well described – that a single night of poor sleep would affect your specific chance of getting pregnant, however, is not proven.
What research says about sleep duration
A systematic review published in Fertility and Sterility in 2021 examined 33 studies on sleep and reproductive function in both women and men. The authors concluded that despite the number of studies, no definitive links could be established. Individual studies in the review pointed in the same direction – among other things, a series of women undergoing IVF showed a link between sleep disorders and fewer retrieved eggs, and a higher pregnancy rate among those who slept seven to eight hours compared to those who slept nine to eleven hours.
In other words: the signals are there, but they are weak and inconsistent. Many studies are based on self-reported sleep, and sleep deprivation often goes hand in hand with stress, shift work, and other factors that can themselves affect fertility. This makes it difficult to know what causes what.
Shift work, night work, and circadian rhythm
Here the evidence is somewhat stronger. A 2023 meta-analysis that compiled 21 studies with over 195,000 women found that shift work was associated with an increased likelihood of irregular periods (odds ratio 1.30; 95% confidence interval 1.23–1.36) and menstrual pain (odds ratio 1.35; 95% CI 1.04–1.75). A link with earlier menopause was also observed.
This does not mean that shift work makes you infertile. The increases are moderate, and most of the included studies were cross-sectional studies, which cannot show causality. But for someone who works nights and is also trying to get pregnant, it may be worth talking to their healthcare provider if their cycle becomes irregular.
How much sleep most people need
1177 states that adults usually need between seven and nine hours of sleep, but that the need varies from person to person and throughout life. A simple guideline they suggest is that you sleep between 6 and 9 hours per night, sleep most of the time you are in bed, and feel alert during the day. There is no benefit in sleeping as long as possible – 1177 points out that too much sleep is not good for your health either.
What you can do in practice
The advice for good sleep health is the same whether you are trying to get pregnant or not, and it costs nothing to try: go to bed and wake up at roughly the same time each day, wind down and dim the lights for the last hour, spend time in daylight, move your body, and eat early in the evening. If sleep difficulties persist over time, effective treatment is available through healthcare – you don't have to solve it on your own.
And one more thing: lying awake worrying that sleep will affect fertility helps neither sleep nor the chance of getting pregnant. Sleep is one of many pieces of the puzzle, and far from the most important.
Frequently asked questions
Can sleep deprivation prevent me from getting pregnant?
There is no evidence that sleep deprivation alone causes infertility. Research shows weak and partly contradictory links between sleep and fertility, and most studies cannot separate the effect of sleep from stress, working hours, and other lifestyle factors.
I work nights – should I quit to get pregnant?
We cannot answer that generally. Data suggest a moderately increased risk of irregular periods with shift work, but the link to pregnancy chances is less clear. Discuss the matter with your midwife or doctor based on your situation.
Do melatonin supplements help with fertility problems?
Melatonin has been studied in connection with egg quality during IVF, but the evidence is limited and mixed. Melatonin is prescription-only in Sweden and should not be taken on your own for fertility purposes without first consulting healthcare.
This article is general information and does not constitute medical advice. Always consult a midwife, doctor, or other healthcare professional about your own situation, especially in cases of sleep difficulties, irregular periods, or involuntary childlessness.