An evaluation of the teratogenic potential of protracted exposure of pregnant rats to 2450-MHz microwave radiation: I. Morphologic analysis at term.

Abstract

The present investigation was designed to study the effects of protracted prenatal exposure of rats to a 20-mW/cm2 power density level of microwave radiation at a frequency of 2450 MHz. Preliminary studies using 24 rats indicated that this power density level did not cause a significant increase in maternal body temperature as measured by a rectal thermocouple. Of 75 pregnant rats, 12 were exposed to microwave radiation, 4 sham-irradiated, and 59 used as environmental control animals. Rats were exposed throughout pregnancy for a total exposure time of approximately 270 h. Daily maternal weights were recorded before irradiation. At term animals were killed, selected maternal tissues were removed, and fetal and placental positions and weights were recorded. After fixation for at least 3 wk, 462 term fetuses were dissected and examined for abnormalities. No significant alterations were observed for the following parameters: maternal weight gain during pregnancy, term maternal organ weights (brain, liver, kidneys, ovaries), term fetal weight, resorption rate, or abnormality rate. These results indicate that the protracted exposure of pregnant rats to 2450-MHz microwave radiation at a power density level of 20 mW/cm2 is not embryopathic.

AI evidence extraction

Main findings

In preliminary work (24 rats), 20 mW/cm2 at 2450 MHz did not significantly increase maternal body temperature. In the main study (75 pregnant rats; 12 exposed, 4 sham, 59 environmental controls), no significant alterations were observed in maternal weight gain, maternal organ weights at term, term fetal weight, resorption rate, or fetal abnormality rate; authors conclude the exposure was not embryopathic under these conditions.

Outcomes measured

• Maternal body temperature
• Maternal weight gain during pregnancy
• Maternal organ weights (brain, liver, kidneys, ovaries) at term
• Fetal weight at term
• Resorption rate
• Fetal abnormality rate
• Placental positions and weights

Limitations

• Small exposed (n=12) and sham (n=4) group sizes
• Power density reported (20 mW/cm2) but SAR not reported
• Details of exposure setup (e.g., modulation, whole-body vs localized, distance) not provided in abstract
• Morphologic analysis at term only; other developmental endpoints not described in abstract

Suggested hubs

• animal-studies (0.9)
  Animal experiment assessing prenatal microwave exposure and fetal outcomes.

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "throughout pregnancy; total exposure time ~270 h"
    },
    "population": "Pregnant rats and term fetuses",
    "sample_size": 75,
    "outcomes": [
        "Maternal body temperature",
        "Maternal weight gain during pregnancy",
        "Maternal organ weights (brain, liver, kidneys, ovaries) at term",
        "Fetal weight at term",
        "Resorption rate",
        "Fetal abnormality rate",
        "Placental positions and weights"
    ],
    "main_findings": "In preliminary work (24 rats), 20 mW/cm2 at 2450 MHz did not significantly increase maternal body temperature. In the main study (75 pregnant rats; 12 exposed, 4 sham, 59 environmental controls), no significant alterations were observed in maternal weight gain, maternal organ weights at term, term fetal weight, resorption rate, or fetal abnormality rate; authors conclude the exposure was not embryopathic under these conditions.",
    "effect_direction": "no_effect",
    "limitations": [
        "Small exposed (n=12) and sham (n=4) group sizes",
        "Power density reported (20 mW/cm2) but SAR not reported",
        "Details of exposure setup (e.g., modulation, whole-body vs localized, distance) not provided in abstract",
        "Morphologic analysis at term only; other developmental endpoints not described in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "pregnant rats",
        "prenatal exposure",
        "microwave radiation",
        "2450 MHz",
        "power density 20 mW/cm2",
        "teratogenicity",
        "embryopathy",
        "fetal abnormalities",
        "resorption rate"
    ],
    "suggested_hubs": [
        {
            "slug": "animal-studies",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Animal experiment assessing prenatal microwave exposure and fetal outcomes."
        }
    ]
}

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