Study type: Medical/biological study (experimental study)

Effects of exposure to microwaves on cellular immunity and placental steroids in pregnant rats med./bio.

Published in: Occup Environ Med 1997; 54 (9): 676-680

Aim of study (acc. to author)

To study the effect of exposure to microwaves during pregnancy on endocrine and immune functions.



Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: CW
Exposure duration: continuous for 90 min
  • SAR: 1.8 mW/g minimum (whole body) (to 2.2 W/kg)
  • power density: 100 W/m² unspecified

Exposure 1

Main characteristics
Frequency 2.45 GHz
Exposure duration continuous for 90 min
Modulation type CW
Exposure setup
Exposure source
  • megnetron
Chamber applicator/ 350 mm x 470 mm x 455 mm
Setup 6 virgin rats and pregnant rats were placed in a semicylindrical acrylic plastic holder (5 mm thick x 60 mm in diameter, 170 mm long)
Additional info Equal number of virgin and pregnant rats served as control, in which identical treatment as the exposed rats was observed except that the microwave generator was switched off. The environment during exposure was maintained at 21 to 23°C and 50 to 60% humidity.
Measurand Value Type Method Mass Remarks
SAR 1.8 mW/g minimum calculated whole body to 2.2 W/kg
power density 100 W/m² unspecified measured - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

Skin temperature in virgin and pregnant rats increased immediately after exposure. Although splenic activity of natural killer cells and any of the subset populations not differ in virgin rats with or without irradiation, pregnant rats exposed to microwaves showed a significant reduction of splenic activity of natural killer cells. Furthermore corticosterone and ACTH increased, and estradiol decreased in exposed virgin and pregnant animals. In contrast, microwaves produced significant increases in beta-endorphin and progesterone only in pregnant animals.
These data in pregnant rats suggest that with irradiation pregnancy induces immunosuppression, which could result in successful maintainance of pregnancy. This increase of adaptability to heat stress may be mediated by activation of placental progesterone and placental or pituitary beta-endorphin.

Study character:

Study funded by

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