Abstract
Objectives
To investigate the association between periconceptional maternal exposure to air pollution and risk of congenital heart disease (CHD) in the highly polluted Delhi National Capital Region (Delhi-NCR).Methods
This case-control study included 1,556 participants (1,115 cases; 441 controls) from Delhi-NCR. Maternal residential addresses were geocoded to estimate periconceptional exposure (at conception, one month pre- and post-conception) to major air pollutants [PM2.5, PM10, NO2, CO, SO2, O3, PM2.5+ PM10, and Air Quality Index (AQI)]. Associations were analysed using multinomial regression.Results
Sixteen Bonferroni-corrected Adjusted odds ratio (AOR) were observed in the study. Preconception exposure to poor AQI [AOR = 2.54 (1.60-4.04)] and PM10 [AOR = 2.82 (1.69-4.71)] increased the odds of simple CHD. At conception, poor AQI was associated with all CHDs [AOR = 2.48 (1.60-3.84)], acyanotic [AOR = 2.68 (1.70-4.24)], and simple CHDs [AOR = 2.71 (1.67-4.39)]. Post-conception exposure showed the strongest associations: poor AQI-All CHD [AOR = 2.74 (1.78-4.22)], acyanotic [AOR = 2.89 (1.84-4.56)], simple CHD [AOR = 2.85 (1.76-4.61)]; PM10-All CHD [AOR = 3.36 (2.05-5.52)], acyanotic [AOR = 3.50 (2.09-5.84)], simple CHD [AOR = 3.95 (2.31-6.76)], and moderate CHD [AOR = 3.64 (1.91-6.91)]. VSD was consistently associated with PM10 preconception [AOR = 3.13 (1.80-5.47)], poor AQI at conception [AOR = 3.18 (1.82-5.53)], and both poor AQI [AOR = 4.01 (2.28-7.08)] and PM10 [AOR = 4.35 (2.41-7.83)] post-conception.Conclusions
To our knowledge, this first Indian study demonstrates that periconceptional exposures to poor AQI and PM10 is significantly associated with increased odds of CHD, with the post-conception period emerging as the most critical window. These findings highlight the urgent need for larger nationwide cohorts and targeted exposure-reduction strategies in early pregnancy.