[Development of murine embryos and fetuses after irradiation with 2450 MHz microwaves].

Abstract

Microwave radiation has been reported to produce adverse effects in a variety of biological systems. We attempted to estimate the influence of repeated expositions to 2450 MHz microwaves at power densities of 10 or 40 mW/cm2 on murine (Swiss) embryos and fetuses development. Mated females were divided into groups and irradiated in various periods of pregnancy. Control animals were placed in the anechoic chamber for similar periods of time. In the 4th day of gestation part of animals were killed, number, phase of development and morphology of embryos after their washing out from uterus were noted. Among embryos obtained from dames irradiated at 40 mW/cm2 (whole body MW hyperthermia) the lower percent of blastulas was counted while more embryos were in the phase of 2-8 blastomers . This suggests retardation of development in the early period of gestation in mice exposed to thermal MW fields. The other part of animals from experimental and control groups were killed on the 19th day of gestation. The fetuses and placentas were removed, weighed, the morphology of fetuses was evaluated. In mice exposed to microwaves at 40 mW/cm2 during the second half of pregnancy increased number of resorptions, stillbirths and internal hemorrhages was noted. The living fetuses had lowered body mass compared to the offsprings of sham-irradiated mice.

AI evidence extraction

Main findings

Repeated exposure to 2450 MHz microwaves at 40 mW/cm2 (described as whole-body microwave hyperthermia) was associated with fewer blastulas and more embryos at the 2–8 blastomer stage on gestation day 4, suggesting developmental delay. Exposure at 40 mW/cm2 during the second half of pregnancy was associated with increased resorptions, stillbirths, and internal hemorrhages, and lower body mass in living fetuses compared with sham-irradiated controls.

Outcomes measured

• Embryo developmental stage distribution (blastula vs 2–8 blastomers) on gestation day 4
• Embryo morphology on gestation day 4
• Resorptions
• Stillbirths
• Internal hemorrhages
• Fetal body mass
• Placenta weight
• Fetal morphology on gestation day 19

Limitations

• Sample size not reported in abstract
• Exposure duration and schedule not fully specified in abstract
• Outcomes for the 10 mW/cm2 group are not described in the abstract
• Thermal effects noted ("whole body MW hyperthermia"), limiting inference about non-thermal effects

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "Repeated exposures during various periods of pregnancy (timing varied by group); assessments on gestation day 4 and day 19"
    },
    "population": "Murine (Swiss) embryos and fetuses from mated female mice",
    "sample_size": null,
    "outcomes": [
        "Embryo developmental stage distribution (blastula vs 2–8 blastomers) on gestation day 4",
        "Embryo morphology on gestation day 4",
        "Resorptions",
        "Stillbirths",
        "Internal hemorrhages",
        "Fetal body mass",
        "Placenta weight",
        "Fetal morphology on gestation day 19"
    ],
    "main_findings": "Repeated exposure to 2450 MHz microwaves at 40 mW/cm2 (described as whole-body microwave hyperthermia) was associated with fewer blastulas and more embryos at the 2–8 blastomer stage on gestation day 4, suggesting developmental delay. Exposure at 40 mW/cm2 during the second half of pregnancy was associated with increased resorptions, stillbirths, and internal hemorrhages, and lower body mass in living fetuses compared with sham-irradiated controls.",
    "effect_direction": "harm",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure duration and schedule not fully specified in abstract",
        "Outcomes for the 10 mW/cm2 group are not described in the abstract",
        "Thermal effects noted (\"whole body MW hyperthermia\"), limiting inference about non-thermal effects"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "2450 MHz",
        "microwaves",
        "power density",
        "10 mW/cm2",
        "40 mW/cm2",
        "whole-body hyperthermia",
        "pregnancy",
        "mouse",
        "embryo development",
        "fetal development",
        "resorptions",
        "stillbirths",
        "hemorrhages",
        "birth weight"
    ],
    "suggested_hubs": []
}

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