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Reproductive Health

[Endocrine mechanism of placental circulatory disturbances induced by microwave in pregnant rats].

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Yoshida Y, Seto T, Ohsu W, Hayashi S, Okazawa T, Nagase H, Yoshida M, Nakamura H, · 1995

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Microwave radiation at 10 mW/cm2 significantly reduced placental blood flow in pregnant rats, suggesting wireless devices may pose pregnancy risks.

Plain English Summary

Summary written for general audiences

Researchers exposed pregnant rats to microwave radiation at the same frequency used in microwave ovens (2,450 MHz) and measured blood flow to the placenta. They found that microwave exposure significantly reduced placental blood flow and disrupted multiple pregnancy hormones including estradiol and progesterone. This matters because reduced placental blood flow can harm fetal development and pregnancy outcomes.

Why This Matters

This study reveals concerning effects on pregnancy from microwave radiation at levels that aren't dramatically higher than what we encounter daily. The exposure level of 10 mW/cm2 is roughly 50 times higher than typical cell phone emissions, but well within ranges that could occur from multiple wireless devices or closer proximity to microwave ovens. The disruption of placental blood flow is particularly significant because adequate blood supply to the placenta is essential for healthy fetal development. The researchers identified specific hormonal pathways affected by the radiation, suggesting the effects aren't just from heating but involve biological mechanisms. While this is animal research, the consistency of findings across multiple pregnancy hormones strengthens the evidence that wireless radiation may pose risks during this vulnerable period.

Exposure Details

Power Density
10 µW/m²
Source/Device
2,450 MHz
Exposure Duration
45-90 min

Exposure Context

This study used 10 µW/m² for radio frequency:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 10 µW/m²Extreme Concern - 1,000 uW/m2FCC Limit - 10M uW/m2Effects observed in the Severe Concern rangeFCC limit is 1,000,000x higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 2.45 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 2.45 GHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

To demonstrate the placental circulatory disturbances induced by microwaves and to clarify the endocrine pathogenesis.

placental blood flow and five endocrine indicators, i.e., corticosterone (CS), estradiol (E2), proge...

The placental blood flow at 45-90 min after exposure was significantly decreased in the rats exposed...

The present results indicate that excessive exposure to whole-body microwave disorders pregnancy in terms of placental circulatory dysfunction. The data suggest the involvement of endocrine mechanisms in the decrease in placental blood flow which is induced via a detrimental effect of microwaves on PGF2 alpha and on pituitary functions such as general emotional stress.

Cite This Study
Yoshida Y, Seto T, Ohsu W, Hayashi S, Okazawa T, Nagase H, Yoshida M, Nakamura H, (1995). [Endocrine mechanism of placental circulatory disturbances induced by microwave in pregnant rats]. Nippon Sanka Fujinka Gakkai Zasshi 47(2):101-108, 1995.
Show BibTeX
@article{y_1995_endocrine_mechanism_of_placental_1453,
  author = {Yoshida Y and Seto T and Ohsu W and Hayashi S and Okazawa T and Nagase H and Yoshida M and Nakamura H and},
  title = {[Endocrine mechanism of placental circulatory disturbances induced by microwave in pregnant rats].},
  year = {1995},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/7706849/},
}
PubMed: 7706849

Cited By (2 papers)

Quick Questions About This Study

Yes, a 1995 study found that 2,450 MHz microwave radiation significantly reduced placental blood flow in pregnant rats 45-90 minutes after exposure. This is concerning because reduced placental blood flow can harm fetal development and pregnancy outcomes.
Research shows 2,450 MHz microwave exposure disrupts multiple pregnancy hormones in rats, including decreased estradiol (E2) and increased corticosterone (CS). These hormonal changes occurred regardless of other treatments, suggesting direct microwave effects on endocrine function.
A rat study found that 2,450 MHz microwave exposure increased PGF2 alpha levels while leaving PGE2 unchanged. Researchers suggest this prostaglandin disruption contributes to reduced placental blood flow through endocrine mechanisms similar to stress responses.
Pregnant rats exposed to 2,450 MHz microwave radiation showed increased progesterone (P) levels. This hormonal change occurred alongside reduced placental blood flow, suggesting microwave exposure triggers stress-like endocrine responses that may affect pregnancy outcomes.
Angiotensin II pretreatment prevented microwave-induced reductions in placental blood flow in rats, but did not stop hormonal disruptions like decreased estradiol and increased corticosterone. This suggests multiple pathways are involved in microwave radiation's pregnancy effects.