Birth defects and high voltage power lines: an exploratory study based on registry data.

This is an exploratory study on birth defects in municipalities through which overhead high voltage power lines (HVPL) pass. It was aimed to test the association between maternal residencial proximity to HVPL and congenital anomalies through a case-control study based on data from the Central-East France Registry of Congenital Malformations. Each of the 1688 malformed infants identified through the register was matched with two randomly selected controls in the same maternal age group of the general population. No excess of any specific type of malformation was observed in infants exposed to HVPL. An inverse association was even found between maternal residence in municipalities with potentially high exposure to electromagnetic fields from overhead power lines and congenital anomalies of all types. This was accounted for by low numbers of exposed infants with two types of malformations: skeletal defects and cardiac defects. Difficulties in interpretation of data are addressed and limitations of the study are discussed. If an inverse association were upheld in further work, a possible mechanism might be that exposure to electromagnetic fields may increase the risk of spontaneous abortion of fetuses with anomalies.