Maternal periconceptional use of electric bed-heating devices and risk forneural tube defects and orofacial clefts

Electric and magnetic fields are of concern as risk factors for adverse rep roductive outcomes, including congenital anomalies. Among residential expos ures to electric and magnetic fields, electric bed-heating devices such as electric blankets may be a substantial source of such exposures, and their use is fairly common. Two population-based case-control studies were analyz ed to investigate whether the periconceptional use of electric blankets, be d warmers, or electrically heated waterbeds increased the risk of women to deliver infants or fetuses with neural tube defects (NTDs) or orofacial cle fts. We obtained information on bed-heating devices from 538 NTD cases and their 539 controls in one study, and 265 NTD cases and 481 controls and 652 orofacial cleft cases and their 734 controls from another study. Our resul ts revealed a few modestly elevated risks of certain anomaly phenotypes wit h maternal use of certain bed-heating devices, but risks tended to be impre cise. In general, women who reported more frequent use of a bed-heating dev ice, or longer duration of use, did not appear to have a higher risk for de livering offspring with anomalies than were women who reported less frequen t or shorter-duration use. Teratology 60:124-129, 1999 (C) 1999 Wiley-Liss, Inc.