14/05/2008 - Using phones in pregnancy and child behavioural problems?

Background:The World Health Organization has previously emphasized the need for research into the possible effects of radiofrequency fields in children. Leading researchers from the United States and Denmark have just examined the association between prenatal and postnatal exposure to cell phones and behavioral problems in young children.

Results: The results are very surprising, with an 80% increase in behavioural problems for those mothers who had used phones whilst pregnant (CI: 1.45-2.23). The study is the first to investigate this issue and as such the results have to interpreted with some caution.

There are a number of possible confounding factors for this association, some of which (gender, socioeconomic class, family history of mental illness, smoking) were considered. Taking these factors into account actually made the results marginally stronger and more significant than those shown above, though there may be unconsidered confounders that have a significant effect.

This is a strong statistical finding, that gives good reason for concern despite there being no known obvious mechanism for this association.

What exposure?

The paper discusses RF exposures to the unborn child but, realistically, these are likely to be vanishingly small from handset use by the mother. If the mother kept their handset in a waist belt pouch, then that could cause significant exposure, but it is mainly men who carry their handsets in trouser belt holsters. 85% of the mothers usually carried their phones in a handbag or case and 82% did not use a personal hands-free kit or earpiece so, when in use, the handset would be well away from the foetus.

As well as pulsed microwaves, GSM phones emit strong 217Hz pulsed low-frequency magnetic fields from the surges of current from the battery. These can be as high as 8 microtesla 1 cm from the handset (i.e. next to the user's head), but fall off fairly quickly (within about 30 cm to very low levels). So these are only likely to affect the foetus is the phone is carried on standby on or near the waist (phone regularly emit these strong pulses when on standby). To put these levels into context, a doubling in the incidence of childhood leukaemia is associated with a 50 Hz field of only 0.4 microtesla. The induced currents in the body increase with frequency, so at 217 Hz the 8 microtesla field mentioned above would be equivalent to 35 microtesla at 50 Hz. Even so, the handset would have to be carried close to the unborn child (e.g. on, or close to, the waist). Also, magnetic fields from electric trains and other sources would be a large confounder.

One possibility is that the EMF exposure of the mother is causing alterations to the development of the foetus, either through direct bio-chemical changes or through epigenetic changes. It is clear that epigenetic changes in a mother can be passed on to their unborn child, especially those due to stress. It is possible that either mobile phone use directly (through EMFs) or indirectly (through a more hectic and stressed maternal lifestyle) have been passed on to the children and abnormal hormone levels have caused the reported behavioural problems.

There is scientific support that maternal prenatal exposure can have an effect on the development of the unborn child (Yehuda 2005, Brand 2006) and also in animal studies (Waterland 2003, Carere 2005), and something along these lines seems to be the most likely explanation if the association is found to be causal.

Some further insights on this paper, including comments from one of the study authors, can be found on Louis Slesin's Microwave News site.

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