Can sleeping less than 6 hours affect fertility? Specialist explains why short sleep and oversleeping both matter

Trying for a baby? Learn from an expert on why sleep duration, quality and bedtime all matter.

You may treat sleep as a footnote in your daily routine, pushing bedtime to watch more episodes or wrap up unfinished work. But for your body, sleep is central to keeping vital systems running and is one of the foundational pillars of overall health.

But, it is not only a lack of sleep that may matter. Sleep duration, timing, quality, and consistency can all influence fertility, while oversleeping may also be associated with poorer reproductive outcomes. So, how much sleep should you get when trying to conceive, and why does your bedtime matter?ALSO READ: Can your periods predict fertility problems later in life? Gynaecologist reveals 6 warning signs you shouldn’t ignore

Dr Rajeev Agarwal, senior infertility specialist and director at Renew Healthcare, explained to HT Lifestyle how poor sleep may affect fertility in both women and men, and shared practical advice for those preparing for conception.

How much sleep is ideal?

“Research consistently links both short sleep, which is under six hours, and long sleep, which is over nine hours, to reduced fertility. Studies examining sleep in relation to time-to-pregnancy and IVF outcomes suggest that the lowest risk is associated with around seven to eight-and-a-half hours of sleep,” he said.

So, sleeping for longer is not necessarily better either. Maintaining a balanced and consistent sleep duration may be more beneficial for reproductive health.

Pregnancy chances may get impacted by poor sleep because of hormonal imbalances.

Why does bedtime matter?

The time at which you sleep also matters. You cannot assume that sleeping late and waking up late will make up for a delayed bedtime simply because you are getting the recommended number of hours. Sleep timing is important too. The expert said that the luteinising hormone (LH) surge, which helps trigger ovulation, occurs predominantly between midnight and 8 am during sleep.

“The hormonal surge that triggers ovulation — the LH surge — occurs predominantly between midnight and 8 am, during deep sleep. Sleeping 10 pm to 6 am is not equivalent to 2 am to 10 am, even if both total eight hours. Late, irregular timing disrupts the pulsatile release of LH and FSH, the hormones governing ovulation,” Dr Agarwal said.

When you have a consistent sleep schedule, your body's natural circadian rhythm is balanced, and thereby, you have support for hormonal functioning.

How do poor sleep and night shift hurt fertility?

The specialist also cautioned that night-shift workers may take longer to conceive and face a higher risk of early pregnancy loss. They may also be more likely to experience menstrual irregularities and dysmenorrhoea, or painful periods, as working late and inadequate sleep can affect hormonal health.

Similarly, poor sleep may affect male reproductive health. Testosterone is largely produced during deep sleep, so inadequate or disrupted sleep may be linked to lower testosterone levels and poorer semen parameters, according to the doctor.

The specialist also warned about stress, “Poor sleep raises cortisol, which can suppress the same GnRH pulsatility that governs both ovulation and sperm production — sleep and stress act on one hormonal pathway from two directions.”

Sleep tips for those trying to conceive

Dr Agarwal recommended the following measures:

• Aim for 7–8 hours nightly — not less, not significantly more
• Keep a consistent bedtime, ideally before 11pm, aligned with natural LH secretion
• Prioritise sleep quality, not just duration — fragmented sleep blunts the same benefits as short sleep
• On unavoidable night shifts, protect a consistent sleep window and minimise light exposure during sleep hours

The specialist said magnesium glycinate may offer modest support for sleep, particularly for those with a low dietary magnesium intake. It should be taken only after consulting a doctor.

Elaborating on melatonin, he said, “Melatonin is worth specific mention: beyond sleep, it acts as an antioxidant inside the ovarian follicle, where it's linked to protecting egg quality from oxidative stress — one of the few supplements connecting sleep and fertility through a direct, not just hormonal-timing, mechanism.”

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.