Maternal cell phone use during pregnancy – effect on pregnancy duration and risk for preterm birth

Tsarna E, Reedijk M, Birks LE, et al Maternal Cell Phone Use During Pregnancy, Pregnancy Duration And Fetal Growth In Four Birth Cohorts. Am J Epidemiol. 2019 Apr 17. pii: kwz092. doi: 10.1093/aje/kwz092.

Previous studies evaluating potential effects of prenatal exposure to radiofrequency fields from cell phones on birth outcomes are inconsistent. We explored if maternal cell phone use was associated with pregnancy duration and fetal growth. We used information from 55,507 pregnant women and their children from Denmark (1996-2002), the Netherlands (2003-2004), Spain (2003-2008) and Korea (2006-2011). Based on self-reported number of cell phone calls per day, exposure was grouped as none, low (reference level), intermediate, and high. We examined pregnancy duration (gestational age at birth, preterm/postterm birth), fetal growth (birth weight ratio, small/large for gestational age), and birth weight, low and high birth weight, and meta-analyzed cohort specific estimates. The intermediate exposure group had higher risk of giving birth at lower gestational age (Hazard Ratio=1.04, 95%CI 1.01, 1.07), and exposure-response relationships were found for shorter pregnancy duration (P<0.001) and preterm birth (P=0.003). We observed no association with fetal growth or birth weight. In conclusion, maternal cell phone use during pregnancy may be associated with shorter pregnancy duration and increased risk for preterm birth. Results should be interpreted with caution, as they may reflect stress during pregnancy or other residual confounding, rather than direct effect of cell phone exposure.

https://www.ncbi.nlm.nih.gov/pubmed/30995291

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Effects of radiofrequency exposure emitted from a GSM mobile phone on proliferation, differentiation, and apoptosis of neural stem cells

A recent article evaluated the effects of radiofrequency radiation emitted from a GSM 900-MHz mobile phone with different exposure duration on proliferation, differentiation and apoptosis of adult neural stem cells (NSCs) in vitro in mice.

Abstract: Due to the importance of neural stem cells (NSCs) in plasticity of the nervous system and treating neurodegenerative diseases, the main goal of this study was to evaluate the effects of radiofrequency radiation emitted from a GSM 900-MHz mobile phone with different exposure duration on proliferation, differentiation and apoptosis of adult murine NSCs in vitro. We used neurosphere assay to evaluate NSCs proliferation, and immunofluorescence assay of neural cell markers to examine NSCs differentiation. We also employed alamarBlue and caspase 3 apoptosis assays to assess harmful effects of mobile phone on NSCs. Our results showed that the number and size of resulting neurospheres and also the percentage of cells differentiated into neurons decreased significantly with increasing exposure duration to GSM 900-MHz radiofrequency (RF)-electromagnetic field (EMF). In contrast, exposure to GSM 900-MHz RF-EMF at different durations did not influence cell viability and apoptosis of NSCs and also their astrocytic differentiation. It is concluded that accumulating dose of GSM 900-MHz RF-EMF might have devastating effects on NSCs proliferation and neurogenesis requiring more causations in terms of using mobile devices.

One of the authors, SMJ Mortazavi, made the following summary of the results:

1. Exposure to GSM 900 MHz mobile phone radiofrequency electromagnetic fields (RF-EMF) decreases the proliferation of neural stem cells (NSCs).
2. Decreased neuronal differentiation in NSCs was also observed in cells exposed to RF-EMF.
3. Exposure to GSM 900 MHz RF-EMF did not influence the viability and apoptosis of NSCs.
4. Active neurogenesis from the stem cells occurs during the first trimester of pregnancy, which could possibly get affected by accumulating dose of exposure to mobile phone RF-EMF.
5. Further research is needed to verify if exposure to mobile phone RF-EMF during the first trimester of pregnancy is associated with increased susceptibility to disorders such as attention deficit hyperactivity disorder (ADHD) or autism in the offspring.

Comment: These results are on mice but are anyhow of interest and add to the evidence that maternal use of mobile phone during pregnancy may increase the risk of child behavioral problems, see blog July 11, 2017.

Maternal cell phone use during pregnancy and child behavioral problems in five birth cohorts

Previous studies have reported associations between prenatal cell phone use (exposure to radiofrequent fields) and child behavioral problems. In this study  data from 83,884 mother-child pairs in the five cohorts from Denmark (1996-2002), Korea (2006-2011), the Netherlands (2003-2004), Norway (2004-2008), and Spain (2003-2008) were analyzed. Cell phone use was grouped into none, low, medium, and high, based on frequency of calls during pregnancy reported by the mothers. Evidence for a trend of increasing risk of child behavioral problems through the maternal cell phone use categories was observed for hyperactivity/inattention problems; ADHD (OR for problems in the clinical range: 1.11, 95%CI 1.01, 1.22; 1.28, 95%CI 1.12, 1.48, among children of medium and high users, respectively). Thus, maternal cell phone use during pregnancy may be associated with an increased risk for behavioral problems, particularly hyperactivity/inattention problems, in the offspring. Increased risk was also found in the high cell phone use category for overall behavioral problems and emotional problems, although not statistically significant. The study can be found here.

In all analyses low cell phone use was used as the reference category. For no cell phone use decreased risk was found for all studied behavioral problems (overall problems, ADHD and emotional problems). It is unclear why low cell phone use instead of no cell phone use was used as the reference category. Using subjects that never used a cell phone would have given higher risk estimates in the high use category.

In the Dutch cohort cordless phone use was assessed yielding similar results as for cell phone use.