Periconception Exposure to Air Pollution and Risk of Congenital Malformations

Objective To evaluate the association between increased exposure to airborne fine particulate matter (PM2.5) during the periconception period with risk of congenital anomalies. Study design Using birth certificate data from the Ohio Department of Health (2006-2010) and PM2.5 data from the US Environmental Protection Agency's 57 monitoring stations located throughout Ohio, the geographic coordinates of the mother's residence for each birth were linked to the nearest PM2.5 monitoring station and monthly exposure averages were calculated. The association between congenital anomalies and increased PM2.5 levels was estimated, with adjustment for coexistent risk factors. Results After adjustment for coexisting risk factors, exposure to increased levels of PM2.5 in the air during the periconception period was modestly associated with risk of congenital anomalies. Compared with other periconception exposure windows, increased exposure during the 1 month before conception was associated with the highest risk increase at lesser distances from monitoring stations. The strongest influences of PM2.5 on individual malformations were found with abdominal wall defects and hypospadias, especially during the 1-month preconception. Conclusions Increased exposure to PM2.5 in the periconception period is associated with some modest risk increases for congenital malformations. The most susceptible time of exposure appears to be the 1 month before and after conception. Although the increased risk with PM2.5 exposure is modest, the potential impact on a population basis is noteworthy because all pregnant women have some degree of exposure.