The problem:

Blue light and what it’s doing to our hormones.

Confused? Heard of ‘The Hormone of Darkness’?

Spoiler; it’s melatonin. Sounds ominous. I prefer, ‘Snoozy Time Hormone’.

Melatonin is a hormone which controls our sleep/wake cycles and plays a part in maintaining our menstrual cycle. In a natural state our body slows production of melatonin in the middle of the day when there is high exposure to environmental blue light - the sun - and increases production at night with the absence of blue light as it gets dark.

Night time = high melatonin = sleepy

Middle of the day = low melatonin = wakey wakey.

Digital devices like car dashboards, laptops and TVs are all sources of blue light, but it is our phones and the way we are using them all day and into the evening, that is having a profound effect on the way our body creates melatonin, and having negative ramifications on our reproductive health.

Melatonin: not just about sleep. The impact on fertility

A lack of melatonin has all sorts of knock on effects in terms of sleep deprivation, but in terms of fertility specifically, there are two primary reasons it’s important to have healthy melatonin production:

Cycle regulation
Egg quality

A regular menstrual cycle

As women we work on a 24 hour and a 28 day cycle. Melatonin plays an important role in both, meaning healthy levels keep the body moving through each phase – the period, follicular phase, ovulation and the luteal phase with a corresponding shift in levels through each phase.

Disruption to the night/day rhythm of melatonin has a domino affect on the 28 day cycle, messing with the hormone shifts needed for a regular cycle. Research out of Japan found that shift workers had greater disruption to melatonin levels as well as an increased incidence of longer cycles, painful periods and ovulation suppression.

Egg and Sperm Quality

Melatonin is also a powerful and unique antioxidant, meaning it protects the body against the oxidative stress that negatively impacts the quality of eggs and sperm. Essentially, melatonin is important for keeping eggs young and healthy and studies have shown a strong causal relationship between high melatonin levels and better egg quality.

What do we know?

Melatonin is a hormone made in the absence of blue light.
Melatonin plays a role in cycle regulation and in egg quality.
Our phones and other devices expose us to blue light well into the evening reducing the production of melatonin.

What should we do? (aka minimising the impact of your phone on your melatonin levels)

From worst to best:

WORST: Take a supplement.

Red alert! Nope, nope, nope. Remember that cyclical rise and fall of melatonin with our cycle? Long term supplementation can mess with this natural regulation, with potential to disrupt or delay ovulation (the exception to the rule – if you have a controlled cycle through IVF, melatonin can be considered).

SLIGHTLY BETTER: Night shift mode

Studies from 2019 showed no change in melatonin suppression levels when using night mode device and minimal changes when also adjusting the brightness settings. If it’s available on your device, switch it on and dial down the brightness as soon as the sun goes down.

MUCH BETTER: Blue light filtering glasses.

Blue light glasses reduce the amount of blue light that passes through to the retina of our eyes. Studies show that people using blue light filtering lenses achieve a statistically more natural level of melatonin than those that don’t, in the same lighting conditions. Plus, while I have no research to back this up, we all know that wearing glasses makes you smarter

BEST: Staying off your device

Of course. Living with the natural rhythm of the sun. Research varies, but ultimately shows that being off your devices for somewhere between 2 and 3 hours in the evening, before you try to sleep will allow for a natural and healthy melatonin cycle.

The importance of melatonin in fertility shouldn’t be overlooked, particularly for older women, given our melatonin levels do slowly decrease as we age.

Trying to conceive? You can read more here.

Is your phone messing with your fertility? 4 ways to minimise device impact