Epidemiological study (observational study)

Maternal cumulative exposure to extremely low frequency electromagnetic fields and pregnancy outcomes in the Elfe cohort.

Published in: Environ Int 2018; 112: 165-173

Aim of study (acc. to author)

A prospective cohort study was conducted in France to examine the association between occupational and residential maternal exposures to extremely low frequency magnetic fields and pregnancy outcomes.

Endpoint/type of risk estimation



Exposure groups

Reference group 1 cumulative exposure: < 17.5 µT-days
Group 2 cumulative exposure: 17.5 - 23.8 µT-days
Group 3 cumulative exposure: 23.8 - 36.2 µT-days
Group 4 cumulative exposure: 36.2 - 61.6 µT-days
Group 5 cumulative exposure: ≥ 61.6 µT-days (90th percentile)
Reference group 6 cumulative exposure: < 44.1 µT-days
Group 7 cumulative exposure: ≥ 44.1 µT-days


  • Group:
    • women
    • children in utero
  • Characteristics: mothers enrolled in a prospective birth cohort (Elfe study), infants born at 33 weeks of gestation or more
  • Observation period: 2011, follow-up at the child's age of 2 months
  • Study location: France
  • Data source: Elfe study
  • Exclusion criteria: multiple births, mothers under age 18, unable to give informed consent, or who intended to move abroad within three years

Study size

Participants 16,733
Evaluable 16,717
Statistical analysis method:
  • logistic regression
( adjustment: )

Conclusion (acc. to author)

Overall 37.5% of the participants were classified in the 23.8–36.2 μT-days category (group 3). High exposures to extremely low frequency magnetic fields during pregnancy were rare: 1.3% in the ≥ 61.6 μT-days category (group 5) and 5.5% in the ≥ 44.1 μT-days category (group 7).
No statistically significant association was found between maternal cumulative exposure and premature birth between 33 and 37 weeks of gestation and small for gestational age in this exposure range.
The authors conclude that this large population-based study does not suggest that maternal exposure to extremely low frequency magnetic fields during pregnancy is highly associated with risks of premature birth between 33 and 37 weeks of gestation or small for gestational age.

Study funded by

  • Ministère délégué à l'Enseignement supérieur et à la Recherche (Ministry of National Education and Research), France
  • Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail (ANSES; French Agency for Food, Environmental and Occupational Health & Safety), France

Related articles

  • Sadeghi T et al. (2017): Preterm birth among women living within 600 meters of high voltage overhead Power Lines: a case-control study.
  • Eskelinen T et al. (2016): Maternal exposure to extremely low frequency magnetic fields: Association with time to pregnancy and foetal growth.
  • de Vocht F et al. (2014): Maternal residential proximity to sources of extremely low frequency electromagnetic fields and adverse birth outcomes in a UK cohort.
  • Mahram M et al. (2013): The effect of extremely low frequency electromagnetic fields on pregnancy and fetal growth, and development.
  • Col-Araz N (2013): Evaluation of factors affecting birth weight and preterm birth in southern Turkey.
  • Auger N et al. (2011): The relationship between residential proximity to extremely low frequency power transmission lines and adverse birth outcomes.
  • Grajewski B et al. (1997): Work with video display terminals and the risk of reduced birthweight and preterm birth.
  • Bracken MB et al. (1995): Exposure to electromagnetic fields during pregnancy with emphasis on electrically heated beds: association with birthweight and intrauterine growth retardation.
  • Savitz DA et al. (1994): Residential magnetic fields, wire codes, and pregnancy outcome.
  • Nielsen CV et al. (1992): Fetal growth, preterm birth and infant mortality in relation to work with video display terminals during pregnancy.