Study type: Epidemiological study (observational study)

Maternal exposure to extremely low frequency magnetic fields: Association with time to pregnancy and foetal growth. epidem.

Published in: Environ Int 2016; 94: 620-625

Aim of study (acc. to author)

A cohort study was conducted in Finland to investigate the association between exposure to extremely low frequency magnetic fields and adverse pregnancy outcomes.

Endpoint/type of risk estimation

Type of risk estimation: (odds ratio (OR))

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 mean of all spot measurements: < 0.2 µT
Group 2 mean of all spot measurements: ≥ 0.2 µT
Reference group 3 mean of all spot measurements: < 0.3 µT
Group 4 mean of all spot measurements:.≥ 0.3 µT
Reference group 5 mean of bedroom spot measurements: < 0.2 µT
Group 6 mean of bedroom spot measurements: ≥ 0.2 µT
Reference group 7 mean of bedroom spot measurements: < 0.3 µT
Group 8 mean of bedroom spot measurements: ≥ 0.3 µT
Reference group 9 front door spot measurement: < 0.2 µT
Group 10 front door spot measurement: ≥ 0.2 µT
Reference group 11 front door spot measurement: < 0.3 µT
Group 12 front door spot measurement: ≥ 0.3 µT
Reference group 13 20 min arithmetic mean: < 0.2 µT
Group 14 20 min arithmetic mean: ≥ 0.2 µT
Reference group 15 20 min arithmetic mean: < 0.34 µT
Group 16 20 min arithmetic mean: ≥ 0.34 µT
Reference group 17 use of electric appliances: < 1 h/week
Group 18 use of electric appliances: ≥ 1 h/week
Reference group 19 occupational magnetic field exposure: no
Group 20 occupational magnetic field exposure: yes
Reference group 21 use of heated water bed: < 10 h/week
Group 22 use of heated water bed: ≥ 10 h/week
Reference group 23 use of electric stove: < 5 h/week
Group 24 use of electric stove: 5 - 10 h/week
Reference group 25 use of electric stove: ≤ 10 h/week
Group 26 use of electric stove: > 10 h/week

Population

Study size

Type Value
Total 562
Participants 373
Statistical analysis method: ( adjustment: )

Conclusion (acc. to author)

The maternal exposure to magnetic fields was slightly higher than in Finnish residences in general, but very high exposures (> 0.4 µT) were rare.
No statistically significant associations were observed between maternal exposure to extremely low frequency magnetic fields and time to pregnancy, birth weight and small for gestational age.
The authors conclude that maternal exposure to extremely low frequency magnetic fields is not likely to be associated with time to pregnancy or prenatal growth at residential exposure levels that were observable in this study.

Limitations (acc. to author)

Only a few mothers were highly exposed in this study.

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