Residence near power lines and risk of birth defects.

Background and ObjectiveThe adverse effects on human health of electromagnetic fields are still unclear and congenital anomalies are among the outcomes which have been associated to such exposure. We conducted a case-control study to examine the risk of birth defects associated with maternal exposure to electromagnetic fields from high-voltage power lines during pregnancy in a northern Italy community. Methods We identified all cases of congenital malformations diagnosed during the period 1998-2006 in live- and stillbirths and induced abortions to women living in Reggio Emilia. As a control group, we selected at random a healthy newborn for each case, matched for year of birth, maternal age and hospital of birth. We geocoded each mother’s resident address during the first trimester of pregnancy in a GIS (Geographical Information System) project. We also calculated the cutpoints of magnetic field density of 0.1, 0.2 and 0.4 microtesla (μT) around high-voltage power lines (>132kV) crossing the municipal territory, inputting the corresponding polylines into the GIS to define exposure corridors. We eventually calculated the risk of prevalence of birth defects associated with maternal exposure to magnetic fields from power lines using a conditional logistic regression model and adjusting for some confounding factors.ResultsWe identified 228 cases of birth defects and a corresponding number of control births. Two case and five control mothers had been residing during the first trimester of pregnancy in corridors with magnetic field intensity >0.1 μT. The risk of congenital malformations associated with the maternal residence during the first trimester of pregnancy in the corridors with exposure >0.1 μT was 0.4 (95% CI 0.1-2.3, P = 0.338) after adjustment for maternal age and education. Conclusions These observations do not suggest that exposure to electromagnetic fields during early pregnancy is associated with excess teratogenic risk.