Maternal cumulative exposure to extremely low frequency electromagnetic fields, prematurity and small for gestational age: a pooled analysis of two birth cohorts

2020 · Mixed · Low evidence

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MixedLow evidencePaper 1648

Study snapshot

Publicationmanual · 2020

Study typecohort

Reported directionMixed

Evidence ratingLow

Abstract

Maternal cumulative exposure to extremely low frequency electromagnetic fields, prematurity and small for gestational age: a pooled analysis of two birth cohorts Migault L, Garlantézec R, Piel C, Marchand-Martin L, Orazio S, Cheminat M, Zaros C, Carles C, Cardis E, Ancel PY, Charles MA, de Seze R, Baldi I, Bouvier G. Maternal cumulative exposure to extremely low frequency electromagnetic fields, prematurity and small for gestational age: a pooled analysis of two birth cohorts. Occup Environ Med. 2020 Jan;77(1):22-31. doi: 10.1136/oemed-2019-105785. Abstract BACKGROUND: Data on the effects of extremely low frequency electromagnetic fields (ELF-EMF) on pregnancy outcomes are inconclusive. OBJECTIVE: To study the relation between maternal cumulative exposure to ELF-EMF during pregnancy and the risk of prematurity or small for gestational age (SGA) in a pooled analysis of two French birth cohorts. METHODS: Elfe and Epipage2 are both population-based birth cohorts initiated in 2011 and included 18 329 and 8400 births, respectively. Health data and household, mother and child characteristics were obtained from medical records and questionnaires at maternity and during follow-up. A job exposure matrix was used to assess cumulative exposure to ELF-EMF during three periods: (1) until 15 weeks of gestation, (2) until 28 weeks of gestation and (3) until 32 weeks of gestation. Analyses were restricted to single live births in mainland France and to mothers with documented jobs (N=19 894). Adjusted logistic regression models were used. RESULTS: According to the period studied, 3.2%-4% of mothers were classified as highly exposed. Results were heterogeneous. Increased risks of prematurity were found among low exposed mothers for the three periods, and no association was observed among the most exposed (OR1=0.92 (95% CI 0.74 to 1.15); OR2=0.98 (95% CI 0.80 to 1.21); OR3=1.14 (95% CI 0.92 to 1.41)). For SGA, no association was observed with the exception of increased risk among the low exposed mothers in period 2 and the most exposed in period 3 (OR=1.25 (95% CI 1.02 to 1.53)). CONCLUSION: Some heterogeneous associations between ELF-EMF exposure and prematurity and SGA were observed. However, due to heterogeneity (ie, their independence regarding the level of exposure), associations cannot be definitely explained by ELF-EMF exposure. ncbi.nlm.nih.gov

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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

PopulationMothers in two French population-based birth cohorts (Elfe and Epipage2); analyses restricted to single live births in mainland France with documented jobs

Sample size19894

ExposureELF · Cumulative exposure during pregnancy assessed for three periods: until 15, 28, and 32 weeks of gestation

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Across pregnancy periods, 3.2%–4% of mothers were classified as highly exposed. Results were heterogeneous: increased risks of prematurity were reported among low-exposed mothers, while no association was observed among the most exposed (ORs ~0.92–1.14 across periods). For SGA, no association was observed except increased risk among low-exposed mothers in period 2 and among the most exposed in period 3 (OR=1.25, 95% CI 1.02 to 1.53).

Outcomes measured

Prematurity
Small for gestational age (SGA)

Limitations

Exposure assessed via a job exposure matrix (potential exposure misclassification)
Heterogeneous associations that were not consistent with exposure level; authors state associations cannot be definitively explained by ELF-EMF exposure
Restricted to mothers with documented jobs and single live births in mainland France (may limit generalizability)

View raw extracted JSON

{
  "study_type": "cohort",
  "exposure": {
    "band": "ELF",
    "source": "occupational",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "Cumulative exposure during pregnancy assessed for three periods: until 15, 28, and 32 weeks of gestation"
  },
  "population": "Mothers in two French population-based birth cohorts (Elfe and Epipage2); analyses restricted to single live births in mainland France with documented jobs",
  "sample_size": 19894,
  "outcomes": [
    "Prematurity",
    "Small for gestational age (SGA)"
  ],
  "main_findings": "Across pregnancy periods, 3.2%–4% of mothers were classified as highly exposed. Results were heterogeneous: increased risks of prematurity were reported among low-exposed mothers, while no association was observed among the most exposed (ORs ~0.92–1.14 across periods). For SGA, no association was observed except increased risk among low-exposed mothers in period 2 and among the most exposed in period 3 (OR=1.25, 95% CI 1.02 to 1.53).",
  "effect_direction": "mixed",
  "limitations": [
    "Exposure assessed via a job exposure matrix (potential exposure misclassification)",
    "Heterogeneous associations that were not consistent with exposure level; authors state associations cannot be definitively explained by ELF-EMF exposure",
    "Restricted to mothers with documented jobs and single live births in mainland France (may limit generalizability)"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF-EMF",
    "occupational exposure",
    "job exposure matrix",
    "pregnancy",
    "prematurity",
    "preterm birth",
    "small for gestational age",
    "birth cohort",
    "France"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.9,
      "reason": "Exposure estimated using a job exposure matrix for maternal jobs during pregnancy in population-based cohorts."
    }
  ]
}

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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: 10.1136/oemed-2019-105785
PubMed: Not supplied

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