Study type: Epidemiological study (observational study)

A population-based prospective cohort study of personal exposure to magnetic fields during pregnancy and the risk of miscarriage. epidem.

Published in: Epidemiology 2002; 13 (1): 9-20

Aim of study (acc. to author)

A population-based prospective cohort study was conducted in the USA to examine the relationship between the personal exposure to magnetic fields during pregnancy and the risk of miscarriage.

Endpoint/type of risk estimation

Type of risk estimation: (relative risk (RR))

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 daily maximum magnetic field exposure: < 1.6 µT
Group 2 daily maximum magnetic field exposure: ≥ 1.6 µT

Population

Study size

Type Value
Total 2,729
Participants 1,042
Evaluable 969
Statistical analysis method: ( adjustment: )

Conclusion (acc. to author)

Although no association was observed between miscarriage risk and the average magnetic field level, miscarriage risk increased with an increasing level of maximum magnetic field exposure with a threshold around 1.6 µT. Women who were exposed to a maximum magnetic field level of 1.6 µT or more had a 80 % increased miscarriage risk compared to women with a maximum magnetic field exposure of less than 1.6 µT. The association was stronger for early miscarriages (< 10 weeks of gestation) and among "susceptible" women with multiple prior fetal losses or subfertility. After excluding women who indicated that their daily activity pattern during the measurements did not represent their typical daily activity during pregnancy, the association was strengthened. Spot measurement did not show a consistent pattern of an association between increased exposure level and the rate of miscarriage.
The findings provide strong evidence that prenatal maximum magnetic field exposure above a certain level (possibly around 1.6 µT) may be associated with miscarriage risk.

Study funded by

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