Blocking Blue Light in Pregnancy, Effects on Melatonin Profile and Sleep

Study Overview
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Brief Summary
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Sleep disturbances are common in pregnancy, and the incidence increases during the third trimester. Light and specially the blue wavelengths of light, is affecting sleep and the circadian rhythm. The main aim of this randomized controlled study is to investigate the effect of Blue-blocking glasses (BB-glasses) used in the evening and night on sleep and mood in pregnant women in the third trimester. The outcome measures assess sleep variables, alertness, melatonin level, sleepiness (subjectively), mood and symptoms of anxiety and depression. In addition we want to measure the pregnancy related sleep problems, alcohol intake, physical activity and perceives stress in the study population, and the association with daily/nightly light exposure.

Detailed Description
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Several hormonal and mechanical influences can cause insomnia in pregnancy, and insomnia has been reported by 62% of pregnant women, a number that is significantly higher than found in the general population (10-15%). Disrupted sleep among pregnant women also includes nocturia (a frequent need to get up and urinate at night), dyspnea (shortness of breath), nasal congestion, muscular aches and pelvic pains, fetal activity, leg cramps as well as reflux. Artificial light in the evening and during the night increases alertness, disturbs sleep, shifts the timing of the circadian clock and impairs the brains' restorative slow waves during deep sleep. Recent studies have however shown that use of BB-glasses in the evening improves sleep quality (subjectively reported) among persons with insomnia, and prevent alertness caused by blue-light emitting screens which are part of devices such as smart-phones and tablets. This project will contribute with new knowledge on how filtering nightly light exposure in pregnant women in their third trimester affects their sleep and mood. Importantly, the project initiates new research on a potential non-pharmacological treatment of sleep disturbances by blocking blue wavelengths of light in the evening and during nocturnal awakenings. Blue light is known to increase alertness through a recently described retinal receptor; the intrinsically photoresponsive retinal ganglion cell (IpRGC), specialized for detecting daytime light signal. This project is highly innovative and may have significant practical implications Due to the variety of aims and outcome measures, we plan to present the outcomes in separate articles.

Official Title
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Nightly Light Exposure in Pregnancy: Blue-blocking Glasses as an Intervention to Ease Sleep Disturbances and to Improve Mood

Conditions
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Sleep Disturbance

Intervention / Treatment
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* Device: Blue-blocking glasses
* Device: Light grey control glasses


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: nulliparous women expecting one child being in the third trimester of a normal pregnancy able to wear an actigraph during daytime and nighttime able to fill out a questionnaire in Norwegian Exclusion Criteria: somatic or psychiatric disorders fever and other health conditions affecting sleep working at night during the study protocol
Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Blue-blocking glasses<br>N=30 The Blue-blocking glasses (orange-tinted), which remove more than 99% of the blue wavelengths (wavelengths within the visible spectrum shorter than 530 nm). Luminous transmittance: 50%. | Device: Blue-blocking glasses<br>* Wear the BB-glasses from three hours before bedtime, and if needed to turn on the light, also during the night.<br>* Other names: Virtual darkness eyewear, orange glasses;|
| Active Comparator: Light grey control glasses<br>N=30 Partially blue blocking light grey glasses, blocking only about 50% of blue wavelengths (wavelengths within the visible spectra shorter than 530 nm). Luminous transmittance: 55%. | Device: Light grey control glasses<br>* Wear the light grey glasses from three hours before bedtime, and if needed to turn on the light, also during the night.<br>* Other names: Grey sunglasses;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep diary | Daily subjective estimates of sleep variables, and will be assessed every morning. | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| Change in motor activity measured by using Actigraphy. | Objective measure by Actiwatch Spectrum from Philips Respironics. The participants will use the Actiwatch for the whole study period of three weeks. | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| Melatonin level | Measured by saliva samples. | 2 weeks in the third trimester of pregnancy, mainly gestational week 29-31 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bergen Insomnia Scale (BIS) | The BIS measure subjective symptoms of insomnia during the previous week, and will be assessed at day 1 and day 21 of the study period. | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| Karolinska Sleepiness Scale (KSS) | Measure subjective sleepiness just prior to turning the lights off, and will be assessed every evening in the study period. | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| Evening activation | Measured subjectively by the Pre-Sleep Arousal Scale (PSAS). | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| Sleepiness (subjectively) | Measured by the Epworth Sleepiness Scale (ESS). | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| Mood | Measured by the self-report forms Positive and Negative Affect Schedule. | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| The Beck Anxiety Inventory (BAI) | Measure subjective symptoms of anxiety, and will be assessed at day 1 and day 21 of the study period. | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 
| The Beck Depression Inventory-II (BAI-II) | Measure subjective symptoms of depression during the last week, and will be assessed at day 1 and day 21 of the study period. | 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Pregnancy, Blue-blockers, Sleep quality, Melatonin