Effects of 2.45 GHz CW microwave radiation on embryofetal development in mice.

Abstract

The embryofetal toxicity and teratogenicity of plane-wave 2.45 GHz continuous wave (CW) microwave radiation at different intensities were investigated in the CD-1 mouse. Mice were exposed on days 1-15 of gestation to an incident power density of 5 mW/cm2 (specific absorption rate of 6.7 mW/gm) and either on days 1-6 or 6-15 of gestation to 21 mW/cm2 (specific absorption rate of 28.14 mW/gm) or to 30 mW/cm2 (specific absorption rate of 40.2 mW/gm) for 8 hours daily. Exposure either on days 1-6 or 6-15 of gestation to a power density of 21 or 30 mW/cm2 caused an increase in colonic temperature of exposed dams of 1 degree C and 2.3 degrees C, respectively. To distinguish between "thermal" and "nonthermal" effects of 21 or 30 mW/cm2, groups of mice were also exposed to elevated ambient temperature to raise their body temperature to the level of those animals exposed to microwave. Ambient temperatures of 30 degrees C and 31 degrees C increased the deep colonic temperature to that obtained with the 21 and 30 mW/cm2 microwave exposure, respectively. The temperature-exposed mice were handled in exactly the same manner as the microwave-exposed mice. A significant reduction in maternal weight gain, either during treatment on days 1-6 or 6-15 of gestation was observed in females of all handled groups. Handling plus exposure to elevated ambient temperature (30 degrees C or 31 degrees C) during days 6-15 of gestation increased this reduction in maternal weight gain. A significant decrease in implantation sites per litter and reduction in fetal weight was noted in the group exposed to 30 mW/cm2 during days 1-6 of gestation. Exposure of mice to a power density of 30 mW/cm2 (days 6-15 of gestation) resulted in a slight, but significant increase in the percentage of malformed fetuses, predominantly with cleft palate, when compared to all other groups.

AI evidence extraction

Main findings

Exposure to 30 mW/cm2 on gestation days 1–6 was associated with fewer implantation sites per litter and reduced fetal weight. Exposure to 30 mW/cm2 on gestation days 6–15 produced a slight but statistically significant increase in malformed fetuses (predominantly cleft palate) compared with other groups. Maternal colonic temperature increased by ~1°C at 21 mW/cm2 and ~2.3°C at 30 mW/cm2; temperature-matched ambient heat groups were included to help distinguish thermal from nonthermal effects.

Outcomes measured

• Embryofetal toxicity
• Teratogenicity/malformations (including cleft palate)
• Maternal weight gain
• Implantation sites per litter
• Fetal weight
• Maternal (colonic) temperature increase

Limitations

• Sample size not reported in abstract
• Randomization/blinding not described in abstract
• Handling effects noted (maternal weight gain reduced in all handled groups), which may confound interpretation
• Results for 5 mW/cm2 group not clearly summarized in abstract
• Details of malformation assessment and statistical methods not provided in abstract

Suggested hubs

• who-icnirp (0.25)
  Animal study of RF/microwave exposure with SAR/power density and thermal considerations, relevant to exposure guideline discussions.

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "8 hours daily; exposures on gestation days 1–15 (5 mW/cm2), days 1–6 or 6–15 (21 or 30 mW/cm2)"
    },
    "population": "Pregnant CD-1 mice (gestation)",
    "sample_size": null,
    "outcomes": [
        "Embryofetal toxicity",
        "Teratogenicity/malformations (including cleft palate)",
        "Maternal weight gain",
        "Implantation sites per litter",
        "Fetal weight",
        "Maternal (colonic) temperature increase"
    ],
    "main_findings": "Exposure to 30 mW/cm2 on gestation days 1–6 was associated with fewer implantation sites per litter and reduced fetal weight. Exposure to 30 mW/cm2 on gestation days 6–15 produced a slight but statistically significant increase in malformed fetuses (predominantly cleft palate) compared with other groups. Maternal colonic temperature increased by ~1°C at 21 mW/cm2 and ~2.3°C at 30 mW/cm2; temperature-matched ambient heat groups were included to help distinguish thermal from nonthermal effects.",
    "effect_direction": "harm",
    "limitations": [
        "Sample size not reported in abstract",
        "Randomization/blinding not described in abstract",
        "Handling effects noted (maternal weight gain reduced in all handled groups), which may confound interpretation",
        "Results for 5 mW/cm2 group not clearly summarized in abstract",
        "Details of malformation assessment and statistical methods not provided in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "2.45 GHz",
        "continuous wave",
        "microwave radiation",
        "plane-wave",
        "power density",
        "specific absorption rate",
        "mouse",
        "gestation",
        "embryofetal development",
        "teratogenicity",
        "cleft palate",
        "maternal temperature",
        "thermal effects"
    ],
    "suggested_hubs": [
        {
            "slug": "who-icnirp",
            "weight": 0.25,
            "reason": "Animal study of RF/microwave exposure with SAR/power density and thermal considerations, relevant to exposure guideline discussions."
        }
    ]
}

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