Maternal residential proximity to sources of extremely low frequency electromagnetic fields and adverse birth outcomes in a UK cohort.

Bioelectromagnetics · 2014 · Mixed · Moderate evidence

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MixedModerate evidencePaper 4710

Study snapshot

PublicationBioelectromagnetics · 2014

Study typecohort

Reported directionMixed

Evidence ratingModerate

Abstract

Studies have suggested that exposure to extremely low frequency electromagnetic fields (ELF-EMF) may be associated with increased risk of adverse birth outcomes. This study tested the hypothesis that close proximity to residential ELF-EMF sources is associated with a reduction in birth weight and increased the risk of low birthweight (LBW), small for gestational age (SGA) and spontaneous preterm birth (SPTB). Closest residential proximity to high voltage cables, overhead power lines, substations or towers during pregnancy was calculated for 140356 singleton live births between 2004 and 2008 in Northwest England. Associations between proximity and risk for LBW, SGA and SPTB were calculated, as well as associations with birth weight directly. Associations were adjusted for maternal age, ethnicity, parity and for part of the population additionally for maternal smoking during pregnancy. Reduced average birth weight of 212 g (95% confidence interval (CI): -395 to -29 g) was found for close proximity to a source, and was largest for female births (-251 g (95% CI: -487 to -15 g)). No statistically significant increased risks for any clinical birth outcomes with residential proximity of 50 m or less were observed. Living close (50 m or less) to a residential ELF-EMF source during pregnancy is associated with suboptimal growth in utero, with stronger effects in female than in males. However, only a few pregnant women live this close to high voltage cables, overhead power lines, substations or towers, likely limiting its public health impact.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typecohort

Effect directionmixed

PopulationSingleton live births (pregnancies) in Northwest England, 2004–2008

Sample size140356

ExposureELF · during pregnancy

Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

Among 140,356 singleton live births, close residential proximity to an ELF-EMF source during pregnancy was associated with lower average birth weight (−212 g; 95% CI: −395 to −29 g), with a larger reduction reported for female births (−251 g; 95% CI: −487 to −15 g). No statistically significant increased risks were observed for LBW, SGA, or SPTB for residential proximity of 50 m or less.

Outcomes measured

Birth weight
Low birthweight (LBW)
Small for gestational age (SGA)
Spontaneous preterm birth (SPTB)

Limitations

Exposure characterized by residential proximity rather than direct ELF-EMF measurements
Only a few pregnant women lived within 50 m of sources, limiting public health impact (and potentially statistical power for clinical outcomes)
Smoking adjustment was available only for part of the population

View raw extracted JSON

{
  "study_type": "cohort",
  "exposure": {
    "band": "ELF",
    "source": "residential proximity to high voltage cables, overhead power lines, substations or towers",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "during pregnancy"
  },
  "population": "Singleton live births (pregnancies) in Northwest England, 2004–2008",
  "sample_size": 140356,
  "outcomes": [
    "Birth weight",
    "Low birthweight (LBW)",
    "Small for gestational age (SGA)",
    "Spontaneous preterm birth (SPTB)"
  ],
  "main_findings": "Among 140,356 singleton live births, close residential proximity to an ELF-EMF source during pregnancy was associated with lower average birth weight (−212 g; 95% CI: −395 to −29 g), with a larger reduction reported for female births (−251 g; 95% CI: −487 to −15 g). No statistically significant increased risks were observed for LBW, SGA, or SPTB for residential proximity of 50 m or less.",
  "effect_direction": "mixed",
  "limitations": [
    "Exposure characterized by residential proximity rather than direct ELF-EMF measurements",
    "Only a few pregnant women lived within 50 m of sources, limiting public health impact (and potentially statistical power for clinical outcomes)",
    "Smoking adjustment was available only for part of the population"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF-EMF",
    "pregnancy",
    "birth weight",
    "low birthweight",
    "small for gestational age",
    "spontaneous preterm birth",
    "power lines",
    "substations",
    "residential proximity",
    "cohort"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.05,
      "reason": "Study concerns residential (not occupational) proximity; hub match is weak."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1002/bem.21840
PubMed: 24482293

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