Abstract
Objective: In pregnancy melatonin regulates circadian rhythms, induce sleep, and has a neuroprotective positive effect on fetal development. Artificial blue light in the evening delays and suppresses melatonin production. Thus, we investigated the effect of blocking blue light on the melatonin profile.
Methods: A randomized controlled trial (n=30 blue-blocking glasses vs. n=30 control glasses with partial blue-blocking effect) including healthy nulliparous pregnant women in the beginning of the third trimester. Salivary melatonin and subjective sleep were measured before and after two weeks of intervention/control condition. Saliva was sampled at 30-min intervals from 3 h before normal bedtime. Melatonin onset was set at 4.0 pg/ml.
Results: Due to missing data melatonin onset was estimated for 47 participants. At posttreatment, melatonin onset advanced by 28 min in the blue-blocking group compared with the control condition (p=.019). Melatonin levels were significantly higher, favoring the blue-blocking glass condition, at clock time 20:00, 21:00 and 22:00 h, and for sample number 3 and 4. The phase angle (time interval) between melatonin onset and sleep bedtime and sleep onset time increased within the blue blocking group (+45 min and +41 min, respectively), but did not reach statistical significance compared to control condition (+13 min and +26 min, respectively).
Conclusion: Blocking blue light in the evening had a positive effect on the circadian system with an earlier onset and rise of melatonin levels in healthy nulliparous pregnant women. This demonstrated the effectiveness and feasibility of a simple non-pharmacological chronobiological intervention during pregnancy.
https://pubmed.ncbi.nlm.nih.gov/35024497/
Pregnancy
Fertility is the same as fecundity and the physiological ability to bear children. Approximately 15% of all couples will experience involuntary childlessness - infertility. The most frequent causes of infertility in women are: consequences of inflammatory conditions in the abdomen, lack of spontaneous ovulation, the woman's age, severe obesity and smoking. An investigation into childlessness typically starts with a visit to your doctor.
Description
Fertilization and melatonin
Melatonin is, among other things, a signalling substance that sends out information to the whole body about the season and time of day (day/night).
The duration of the secretion of melatonin is usually approximately nine hours during the night, and the secretion reaches the maximum concentration in the blood around 3 a.m. You prevent the secretion of melatonin by exposing yourself to daylight or artificial lighting.
The timing of the birth of offspring for most animals, including humans, is regulated to some extent by the duration of melatonin secretion. Melatonin is normally secreted when you are surrounded by darkness.
Before the introduction of the electric light, the duration of melatonin secretion gradually increased during autumn as the nights grew longer. For most animals, this signalled the period of greatest fertility, so that the offspring would be born in the spring. For man, the electric light meant the end of the natural effect of the length of the days - at least in terms of fertility.
Pregnancy and sleep
Lack of sleep can also affect women's fertility.
Seventy percent of Americans suffer from sleep problems, most of which remain undiagnosed and untreated. Sleep is not only essential for quality of life and general health, but also plays an important role in fertility.
The woman's brain and organ systems (including the reproductive system) are restored during sleep, so long-term sleep disorders can be associated with problems in relationships, mood, and the immune system, and hormonal imbalance. Too little sleep can also lead to irregular periods, which can delay pregnancy.
To reveal the effect sleep has on fertility, researchers examined women who had a profession that entailed too little sleep, e.g. flight attendants and nurses who work at night. According to the study, half of the women examined had irregular periods, while other women's ovulation did not occur at all.
Exposure to light also affects ovulation and the reproductive hormones. Lack of sunlight can trigger depression, which in turn suppresses fertility. Furthermore, researchers have found that they can change the length of women's menstrual cycles by exposing them to artificial light (around mid-cycle) while they sleep. The researchers discovered that the hormones that trigger ovulation are linked to the body's biological clock.
Fertility and sleep glasses
Using sleep glasses can be an easy method to increase fertility.
Start by wearing the glasses for a period of five minutes before bedtime. Extend the period by five minutes each evening, simulating the approach of winter, the season of optimal fertility.
The method is not yet proven with clinical trials, but going back to the natural cycle that we were originally created for will not do any harm, can probably help to increase fertility.
The largest number of births occurs in the month of July. This suggests that November is the month when fertility is greatest.
Check the sleep
To ensure that you get enough sleep and enough daylight in connection with your daily routines, you can use this guide:
1. Discover the need for sleep: The optimal duration of sleep is eight hours for adults (however, this can vary by several hours from person to person).
2. Go outside: The recommended duration of exposure to sunlight is approximately one hour every day.
3. Avoid irregular working hours. Evening and night work is associated with irregular menstruation and reproductive disorders.
4. Go to bed and wake up at regular times. This applies to both weekdays and weekends.
5. Calm the brain: Avoid activities before bed that engage the brain too much.
6. Use dim lighting in the evening or sleep glasses.
Research regarding pregnancy
A randomized controlled trial on the effect of blue-blocking glasses compared to partial blue-blockers on melatonin profile among nulliparous women in third trimester of the pregnancy
Neurobiol Sleep Circadian Rhythms. 2021 Dec 29:12:100074. doi: 10.1016/j.nbscr.2021.100074. eCollection 2022 May.Randi Liset, Janne Grønli, Roger Ekeberg Henriksen, Tone Elise Gjøtterud Henriksen, Roy Miodini Nilsen, Ståle PallesenPMID: 35024497 / PMCID: PMC8728098 / DOI: 10.1016/j.nbscr.2021.100074
During pregnancy, melatonin regulates the circadian rhythm, induces sleep and has a neuroprotective positive effect on foetal development. Artificial blue light in the evening delays and suppresses melatonin production. Thus,...
A randomized controlled trial on the effect of blue-blocking glasses compared to partial blue-blockers on melatonin profile among nulliparous women in third trimester of the pregnancy
During pregnancy, melatonin regulates the circadian rhythm, induces sleep and has a neuroprotective positive effect on foetal development. Artificial blue light in the evening delays and suppresses melatonin production. Thus, we investigated the effect of blocking the blue light with sleep glasses and glasses that partially block the blue light. The experiment showed that using sleep glasses in the evening had a positive effect on the circadian rhythm, with an earlier onset and increase in the melatonin level in healthy first-time mothers in the third trimester. The experiment also showed the effectiveness and feasibility of a simple influence on the circadian rhythm during pregnancy, completely without medication.
A randomized controlled trial on the effect of blue-blocking glasses compared to partial blue-blockers on melatonin profile among nulliparous women in third trimester of the pregnancy
Neurobiol Sleep Circadian Rhythms. 2021 Dec 29:12:100074. doi: 10.1016/j.nbscr.2021.100074. eCollection 2022 May.
PMID: 35024497 / PMCID: PMC8728098 / DOI: 10.1016/j.nbscr.2021.100074