Associations of exposure to PM2.5 and its constituents during pregnancy with the risk of premature rupture of membranes in twin pregnancies.

PM2.5 and its constituents are linked to various comorbidities and complications during pregnancy. However, evidence remains limited regarding the association of total PM2.5 mass and PM2.5 constituents with premature rupture of membranes (PROM) in twin pregnancies. Accordingly, contributing new insights to this field is of significant value. In this study, we employed logistic regression, restricted cubic spline regression, weighted quantile sum, quantile g-computation, Bayesian kernel machine regression, and subgroup analyses to quantify the individual and joint associations of PM2.5 and its constituents with the risk of PROM in twin pregnancies, identify sensitive exposure windows during pregnancy, and explore potential effect modifiers. We found that the risk of PROM in twin pregnancies was positively associated with total PM2.5 mass and PM2.5 constituents, with stronger associations observed in trimester 1. Co-exposure to NH4+, NO3-, SO42-, BC, and OM was also linked to an elevated risk of PROM, with NO3-, SO42-, and OM identified as the most influential constituents. Similarly, trimester 1 was also identified as a sensitive exposure window during pregnancy for co-exposure to NH4+, NO3-, SO42-, BC, and OM. In addition, PM2.5-related PROM risk was higher among pregnant women with high education levels and advanced maternal age. Our findings suggest that the risk of PROM in twin pregnancies is associated with PM2.5 exposure during pregnancy, and highlight the necessity for developing targeted mitigation strategies, especially for trimester 1 and pregnant women with high education levels and advanced maternal age.