What does chronic sleep deprivation do to your fertility when you are trying to conceive?

Women who frequently sleep poorly have a noticeably lower chance of becoming pregnant. In a large cohort study of nearly 7,000 women trying to conceive, severe insomnia (difficulty falling or staying asleep more than half the time) was linked to a 13% lower chance of pregnancy per cycle. Short sleep duration of less than 6 hours per night showed a similar pattern, but that difference was not statistically convincing.

Chronic sleep deprivation is also associated with broader reproductive problems. A meta-analysis of 38 studies found that women with sleep deprivation had more than three times the rate of premature ovarian insufficiency, a condition in which the ovaries stop functioning normally at a young age. In addition, irregular menstruation, polycystic ovary syndrome (PCOS), and lower success rates in fertility treatments have all been linked to disrupted sleep patterns or night and shift work.

Exactly how this works has not yet been fully established, but researchers point to hormonal disruptions that affect ovulation, fertilisation, and implantation. An evening chronotype (being a natural 'night owl') and rotating shift schedules also play a role here, alongside simply getting too few hours of sleep.

An important caveat: all of these associations are based on observational research. The studies show correlations, not proven cause-and-effect relationships. Methodological quality also varies considerably between studies. For people who want to conceive, good sleep is therefore a sensible priority, but sleep is of course not the only factor that determines fertility. If you want to prevent gestational diabetes or high blood pressure during pregnancy, sufficient and regular sleep is also relevant both before and during pregnancy.