Exposure to outdoor artificial light at night and excessive gestational weight gain: A retrospective cohort study

BACKGROUND: Excessive gestational weight gain (GWG) has been linked to adverse severe gestational complications and birth outcomes. However, the effects of outdoor artificial light at night (ALAN) on excessive GWG is unknown. OBJECTIVE: We aimed to explore the trimester-specific associations of ALAN exposure with excessive GWG. METHOD: This study recruited 51,096 pregnant women registered in the Guiyang Maternal and Child Health Hospital from 2013 to 2022. Outdoor ALAN exposure was estimated by time-varying satellite data according to the home addresses. Binary logistic regression and general linear regression were used to assess the associations of ALAN with excessive GWG and GWG, respectively. Restrictive cubic splines (RCS) was fitted to explore the nonlinear relationships. RESULTS: The median GWG was 15.0 kg (interquartile rage (IQR): 7.0), and 20,496 (40.11 %) women had excessive GWG. Both binary logistic models and general linear models showed that per IQR increase of ALAN exposure in preconception and each trimester was associated with higher risk of excessive GWG and increased GWG. Stratified analysis revealed stronger associations among women with junior high school education, unemployment, and multiparity. In addition, RCS models revealed nonlinear relationships between ALAN exposure and both excessive GWG risk and GWG. CONCLUSIONS: Our findings emphasize that exposure to outdoor ALAN during preconception and pregnancy is a contributing environment factor to excessive GWG. Furthermore, education, occupation, and parity serve as modifiable factors for these associations.