ELECTROMAGNETIC BIOLOGY AND MEDICINE Vol. 22, No. 1, pp. 51–53, 2003 Magnetic Fields in Incubators a Risk Factor in IVF/ICSI Fertilization? Kjell Hansson Mild, 1,2, * Mats-Olof Mattsson, 2 and Lennart Hardell 2,3 1 National Institute for Working Life, Umea ˚, Sweden 2 Department of Natural Science, O ¨ rebro University, O ¨ rebro, Sweden 3 Department of Oncology, O ¨ rebro University Hospital, O ¨ rebro, Sweden ABSTRACT Power frequency magnetic fields can reach tens of mT in incubators used for in vitro fertilization. This article suggests that this can be one factor connected to the observed increase of congenitial defects in children born after such procedure. Key Words: Embryonic development; Congenitial defects. An increased risk of congenital defects in children born after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) has been suggested by the results of several controlled studies (Berg and Wennerholm, 2002; Hansen et al., 2002). The question they ask is whether the increased risk is caused by any of the drugs that are used or by the IVF/ICSI procedure itself. Here, we would like to highlight the possibility that the increased risk can be connected to the power frequency magnetic fields inside the incubators used in the in vitro process. * Correspondence: Kjell Hansson Mild, Ph.D., National Institute for Working Life, S-90713 Umea ˚, Sweden and Department of Natural Science, O ¨ rebro University, S-701 82 O ¨ rebro, Sweden. 51 DOI: 10.1081/JBC-120020355 1536-8378 (Print); 1536-8386 (Online) Copyright D 2003 by Marcel Dekker, Inc. www.dekker.com