Nocturnal light pollution and clinical signs of ovulation disorders

Marie Garmier-Billard; Joy DeFelice; Françoise Soler; Jean Iwaz; René Ecochard

doi:10.15761/TiM.1000193

Lifestyle and Environment · Environmental Exposures

Nocturnal light pollution and clinical signs of ovulation disorders

Garmier-Billard M, DeFelice J, Soler F, Iwaz J, Ecochard R

Published June 3, 2019 Trends in Medicine, 19(4)

DOI 10.15761/TiM.1000193

RRM Academy Synopsis

Bedroom light at night may be linked to ovulation disorder signs

A cross-sectional study of 19 healthy French women suggests that light in the bedroom at night may be linked to some clinical signs of ovulation disorders. The women charted 56 cycles. Six of 110 tests gave a p-value below 0.05.

Key Findings

The analysis covered 19 women and 56 menstrual cycles. Eighteen women contributed three cycles each and one contributed two. Light was assessed over 94 nights.
At least one outdoor light source reflected into the bedroom on 67 of 94 nights (71.2%). Street light flooded into the bedroom on 31% of nights.
Seven days or more of mucus discharge, and a lot of mucus during the luteal phase, each appeared in 27 of 56 cycles (48.2%).
Six of the 110 Wilcoxon tests had p-values below 0.05. The lowest was 0.006, and none reached the Bonferroni limit of 0.00045.

Interpretation

A cross-sectional study records light and cycle signs in the same women at one point in time. It shows association and cannot show that light caused any sign. The 19 women came from one cycle institute, and all had experience with natural family planning methods. The authors report that the small sample left too little power to reach the Bonferroni limit. They note that women with cycle problems may have been more willing to take part. Light was averaged over five nights and was not timed to cycle phase. The authors call for a randomized study of removing bedroom light.

RRM Context

The study read ovulation disorder signs from charts of basal body temperature and cervical mucus. One author defined the signs according to the Creighton model. The authors also describe an unpublished pilot by one of them. After nighttime light was reduced, abnormal parameters fell in six cycles. Pregnancies followed in women who had been infertile.

Our editorial summary of this paper, not the article's abstract.

Abstract

Objective

Assess quantitatively the impact of nocturnal light pollution on the menstrual cycle.

Design

Cross-sectional observational study.

Setting

Single French institute from November 2017 to March 2018.

Participants

Nineteen ostensibly healthy menstruating women aged 19 to 45, inclusive.

Interventions

None.

Main Outcome Measures

Assessment of nocturnal light pollution (questionnaire and lux meter) and 22 clinical signs of ovulation disorder. Wilcoxon tests were used to quantify the abilities of nocturnal light pollution factors to predict clinical signs of ovulation disorders.

Results

Nearly half of the 94 daily observations made by questionnaire and measurements made by lux meter indicated light pollution due to light flooding into the bedroom from indoor or outdoor sources. Nearly more than half of the 56 menstrual cycles presented at least mild abnormalities. The data showed that some clinical signs of ovulation disorders may be significantly predicted by factors of light pollution but a lack of power prevented reaching Bonferroni criterion.

Conclusions

The indications of negative impact of dim light at night on some menstrual cycle characteristics call for a randomized study to quantify improvements of menstrual cycle characteristics brought by suppressing nocturnal light pollution. This will pave the way for new therapeutic perspectives for some difficult cases of ovulation disorders.

Topics

Lifestyle and Environment › Environmental Exposures › Radiation and Electromagnetic Exposure · Menstrual Cycle › Cycle Disorders › Ovulatory Disturbances · Reproductive Endocrinology › Ovulation Physiology › Ovulation Disorder Classification

Marie Garmier-Billard, Joy DeFelice, Françoise Soler, Jean Iwaz, René Ecochard

M Garmier-Billard, J DeFelice, F Soler, J Iwaz, R Ecochard

DOI 10.15761/TiM.1000193 10.15761/TiM.1000193 Garmier-Billard et al. 2019, Garmier-Billard 2019

Nocturnal light pollution and clinical signs of ovulation disorders

Bedroom light at night may be linked to ovulation disorder signs

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

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