title: Extremely low frequency magnetic fields and fertility: a follow up study of couples planning first pregnancies. The Danish First Pregnancy Planner Study Team.
abstract: OBJECTIVE
  To evaluate the impact of extremely low frequency (ELF) magnetic fields on markers of human fertility.
  
  
  METHODS
  A follow up study of time to pregnancy, semen quality, and reproductive hormones was conducted among couples planning first pregnancies (36 males were welders and 21 were non-welders). The male and the female partner were monitored for exposure to ELF magnetic field by personal exposure meters. As summary measures of exposure the median value was calculated together with the 75 percentile value and the proportion of measurements exceeding 0.2 and 1.0 microT, respectively. Each summary measure was divided in three categories: low, medium, and high.
  
  
  RESULTS
  Couples in which the man had a medium or a high proportion of measurements > 1.0 microT had a reduced probability of conception per menstrual cycle compared with the men with low exposure, but the result was only significant for the men with medium exposure. This finding was partly attributable to a high probability of conception per menstrual cycle among the men with low exposure compared with non-welders in the original cohort of 430 couples. Other summary measures were not related to probability of conception or other markers of fertility. A possible negative association was found between high probability of conception and female exposure measures based on the median, the 75 percentile, and the proportion of measurements > 0.2 microT, but no association was found with the proportion of measurements > 1.0 microT.
  
  
  CONCLUSIONS
  The findings provide no consistent support for a hypothesis of a deleterious effect of low level ELF magnetic fields on markers of human fertility. However, due to the relatively small size of the studied population only large associations would be detected.
authors.affiliation: Department of Occupational Medicine, Aarhus University Hospital, Denmark. akh.gp22s.akamkpp1@aaa.dk
authors.forename: N H
authors.initials: NH
authors.lastname: Hjollund
authors.forename: J H
authors.initials: JH
authors.lastname: Skotte
authors.forename: H A
authors.initials: HA
authors.lastname: Kolstad
authors.forename: J P
authors.initials: JP
authors.lastname: Bonde
mesh_terms: D000328:Adult; D005260:Female; D005298:Fertility; D005500:Follow-Up Studies; D012739:Gonadal Steroid Hormones / Q000097:blood; D006801:Humans; D008280:Magnetics / Q000009:adverse effects*; D008297:Male; D008669:Metallurgy; D016273:Occupational Exposure / Q000009:adverse effects*; D011247:Pregnancy; D018873:Pregnancy Rate; D012661:Semen; D013997:Time Factors
chemical_list: D012739:Gonadal Steroid Hormones