In the Journals

Exposure to air pollution before conception increases risk of birth defects

When women are exposed to air pollution in the form of airborne fine particulate matter 1 month before conception, their offspring are at slightly increased risk of developing congenital anomalies, according to a study published in The Journal of Pediatrics.

“Although some specific malformations have a clear cause-effect relationship with periconception exposure such as poor glycemic control in diabetics and the caudal regression syndrome or thalidomide and limb reduction anomalies, most congenital anomalies have no known single teratogenic etiology,” Shen Ren, PhD, from the department of mathematics at the University of Cincinnati and the division of biomedical informatics at Cincinnati Children’s Hospital Medical Center, and colleagues wrote.

“Considering that embryonic maldevelopment leading to congenital anomalies is a multifactorial disease process, investigators have become increasingly interested in the contribution of modifiable risk factors such as exposure to environmental pollutants,” they continued.

To examine the connection between the risk of congenital anomalies and contact with airborne fine particulate matter (PM2.5) within the periconception period, the researchers analyzed birth certificates gathered between 2006 and 2010 by the Ohio Department of Health. Additionally, data regarding PM2.5 air pollution within the periconception period were amassed from 57 monitoring stations located in Ohio and run by the United States Environmental Protection Agency.

Additional data analyzed included the mother’s place of residence as represented by geographic coordinates for each birth included in the study. With this information, they linked mothers with the nearest PM2.5 monitoring station and calculated monthly exposure averages. The link between congenital birth defects and increased levels of air pollution was evaluated.

When Ren and colleagues adjusted for coexisting risk factors, data suggested that exposure to higher levels of PM2.5 were related to a slightly increased risk of congenital birth defects. The risk of developing congenital anomalies were highest when exposed to PM2.5 1 month before conception and when exposed at lesser distances from the EPA’s monitoring stations.

Exposure to PM2.5 during the periconception period was most associated with abdominal wall defects and hypospadias. These were most frequently observed when mothers were subjected to pollution 1 month before conception.

“We found a modest but positive association with increasing levels of PM2.5 exposure 1 month before and 1 month after conception with risk of any congenital anomaly, when assessed as a composite variable,” Ren and colleagues wrote. “Future studies should focus on anomalies other than just cardiac and facial clefts, have clear definitions of case classification and use of classifications and exclusions in sensitivity analyses. Few studies included the spectrum of all reported anomalies, and most only looked at cardiac anomalies.” – by Katherine Bortz

Disclosures: The authors report no relevant financial disclosures.

When women are exposed to air pollution in the form of airborne fine particulate matter 1 month before conception, their offspring are at slightly increased risk of developing congenital anomalies, according to a study published in The Journal of Pediatrics.

“Although some specific malformations have a clear cause-effect relationship with periconception exposure such as poor glycemic control in diabetics and the caudal regression syndrome or thalidomide and limb reduction anomalies, most congenital anomalies have no known single teratogenic etiology,” Shen Ren, PhD, from the department of mathematics at the University of Cincinnati and the division of biomedical informatics at Cincinnati Children’s Hospital Medical Center, and colleagues wrote.

“Considering that embryonic maldevelopment leading to congenital anomalies is a multifactorial disease process, investigators have become increasingly interested in the contribution of modifiable risk factors such as exposure to environmental pollutants,” they continued.

To examine the connection between the risk of congenital anomalies and contact with airborne fine particulate matter (PM2.5) within the periconception period, the researchers analyzed birth certificates gathered between 2006 and 2010 by the Ohio Department of Health. Additionally, data regarding PM2.5 air pollution within the periconception period were amassed from 57 monitoring stations located in Ohio and run by the United States Environmental Protection Agency.

Additional data analyzed included the mother’s place of residence as represented by geographic coordinates for each birth included in the study. With this information, they linked mothers with the nearest PM2.5 monitoring station and calculated monthly exposure averages. The link between congenital birth defects and increased levels of air pollution was evaluated.

When Ren and colleagues adjusted for coexisting risk factors, data suggested that exposure to higher levels of PM2.5 were related to a slightly increased risk of congenital birth defects. The risk of developing congenital anomalies were highest when exposed to PM2.5 1 month before conception and when exposed at lesser distances from the EPA’s monitoring stations.

Exposure to PM2.5 during the periconception period was most associated with abdominal wall defects and hypospadias. These were most frequently observed when mothers were subjected to pollution 1 month before conception.

“We found a modest but positive association with increasing levels of PM2.5 exposure 1 month before and 1 month after conception with risk of any congenital anomaly, when assessed as a composite variable,” Ren and colleagues wrote. “Future studies should focus on anomalies other than just cardiac and facial clefts, have clear definitions of case classification and use of classifications and exclusions in sensitivity analyses. Few studies included the spectrum of all reported anomalies, and most only looked at cardiac anomalies.” – by Katherine Bortz

Disclosures: The authors report no relevant financial disclosures.