Epidemiological study

Prenatal exposure to extremely low frequency magnetic field and its impact on fetal growth epidem.

By: Ren Y, Chen J, Miao M, Li DK, Liang H, Wang Z, Yang F, Sun X, Yuan W

Published in: Environ Health 2019; 18: 6

Aim of study (acc. to author)

A prospective cohort study was conducted in China to examine the association between maternal exposure to extremely low frequency magnetic fields during pregnancy and fetal growth in offspring.

Endpoint/type of risk estimation

reproductive effects and pregnancy outcomes: fetal growth: birth weight, skinfold thickness of back, triceps and abdomen, circumference of head, upper arm and abdomen

Exposure

- personal

Assessment

dosimeter: 24 h measurement during 3rd pregnancy trimester
calculation: time-weighted average (TWA), median and 75th percentile of the 24-h MF measures

Exposure groups

Group	Description
Reference group 1	time-weighted average: < 0.063 µT
Group 2	time-weighted average: > 0.063 µT
Reference group 3	Median: < 0.038 µT
Group 4	Median: > 0.038 µT
Reference group 5	75th percentile: < 0.063 µT
Group 6	75th percentile: > 0.063 µT

Population

Group:
- women
- children in utero
- newborns
Observation period: 2012
Study location: China (Shanghai)

Study size

Type	Value
Contacted	250
Participants	140
Evaluable	128

Statistical analysis method:

generalized linear model

(adjustment:

gestational age, parity, maternal BMI before pregnancy, maternal passive smoking during pregnancy, maternal and paternal ages at childbirth, paternal BMI, family income

)

Results (acc. to author)

Compared with girls with lower prenatal exposure to extremely low frequency magnetic fields (reference groups), girls with higher exposure (groups 2, 4 and 6) had a lower birth weight, thinner skinfold of triceps, abdomen and back, and smaller circumference of head, upper arm and abdomen. The differences were statistically significant for birth weight and most other growth measurements. These measures had no significant difference between higher and lower prenatal exposure to extremely low frequency magnetic fields in boys except back skinfold thickness.
The authors concluded that prenatal exposure to higher extremely low frequency magnetic field levels was associated with decreased fetal growth in girls, but not in boys.

Study funded by

not stated/no funding

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