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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
60
Wear the BB-glasses from three hours before bedtime, and if needed to turn on the light, also during the night.
Wear the light grey glasses from three hours before bedtime, and if needed to turn on the light, also during the night.
Randi Liset
Bergen, Norway
Sleep diary
Daily subjective estimates of sleep variables, and will be assessed every morning.
Time frame: 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.
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
Melatonin level
Measured by saliva samples.
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
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.
Time frame: 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.
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
Evening activation
Measured subjectively by the Pre-Sleep Arousal Scale (PSAS).
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
Sleepiness (subjectively)
Measured by the Epworth Sleepiness Scale (ESS).
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
Common pregnancy complaints Questionnaire
Measure subjective complaints during the last night, assessed every morning of the study period.
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
Cortisol level
Measured by saliva samples, assessed at day 7 and day 21 of the study period.
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
Alpha Amylase level
Measured by saliva samples, assessed at day 7 and day 21 of the study period
Time frame: 3 weeks in the third trimester of pregnancy, mainly gestational week 28-31
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