155 Evening blue light exposure, maternal glucose and infant birth weight

During pregnancy, the use of light-emitting electronic devices before bedtime may contribute to or exacerbate sleep problems. Exposure to blue-wavelength light in particular from these devices may affect sleep by inhibiting melatonin release and causing neurophysiologic arousal which may affect the uterus environment. However, the health consequences of blue-wavelength light on maternal glucose level and fetus development is poorly understood. The purpose of this study was to test the hypothesis that nocturnal blue-light exposure is associated with maternal glucose level and infant’s birth weight. Methods A group of pregnant women aged 24-39 years old who wore 7-day actigraphy, and completed questionnaires including Pittsburgh Sleep Quality Index participated in the study. Infant’s birth weight (n=41) and fasting glucose level (n=30) was abstracted from mothers’ medical charts. Blue-wavelength light exposure was obtained from actigraphy recordings. Unadjusted linear regression analyses were performed to determine sleep characteristics that were associated with fasting glucose and infant’s weight (p<0.2). Using infant’s birth weight and fasting glucose as outcome variables, confounding variables were evaluated in full linear regression models as independent variables. Results The mean gestational age was 30.66 (Standard Deviation (SD) 3.46) weeks. The mean fasting glucose, infant’s birth weight and gestational age at delivery were 95.73 mg/dL (SD 24.68), 3261 gr (SD 470) and 38.78 (SD 1.69), respectively. In unadjusted analysis, infant birth weight was significantly associated with only blue light value (μW/cm2) (β=76.98, p=0.002) and remained significant (β=78.26, p=0.003) after adjusting for BMI, maternal age and gestational diabetes. Fasting glucose was associated with blue light value (β=2.81, p=0.055) and became significantly associated (β=78.26, p=0.003) after adjusting for sleep duration, parity and gestational diabetes. The coefficient demonstrates that for each unit increase in the evening blue light exposure, there is a 78 gr increase in infant weight after controlling the effect of maternal age, BMI and gestational diabetes. Conclusion Evening blue light exposure during mid and late pregnancy may alter maternal glucose regulation and placental nutrient transport to fetus, but these remain to be studied. This study may shed light on future research on the effect of evening light exposure on pregnancy outcomes. Support (if any) National Institutes of Health (R00-NR013187)