Cell phone use and exposure to weak radio frequency electromagnetic fields (EMF-RF) has been a public health concern for several years. Specific concerns on whether using your cell phone while pregnant can harm your fetus are mainly due to their extensive use.

Despite the widespread uncertainty among the public that EMF-RFs from cell phones might harm the developing brain of the fetus, the evidence from animal experiments and from previous epidemiological studies with mothers and children are inconsistent.

To find answers, we studied the association between maternal cell phone use during pregnancy and child’s neurodevelopment at 3 and 5 years. We included around 45,000 mothers and their children from all over Norway who are participants of a large birth cohort study, the Norwegian Mother and Child Study (MoBa study). This is the largest study worldwide that follows families from pregnancy.

The child’s neurodevelopment was assessed by questionnaires answered by the parents. These are frequently used questionnaires in epidemiological studies, with questions like: “When you ask you child to point at his/her eyes, nose, hair, etc. does he/she point correctly on at least seven parts of the body?” and “Can your child catch a large ball with both hands?”. In addition, we used language development as an outcome because in previous studies we found this parameter to be sensitive to exposure to neurotoxicants.

We found no evidence of a harmful effect of the mother using her cell phone during pregnancy on her child’s neurodevelopment at 3 and 5 years

We found no evidence of a harmful effect of the mother using her cell phone during pregnancy on her child’s neurodevelopment at 3 and 5 years. Further to this, we even found that the more the mother was using her cell phone during pregnancy the better language and motor skills her child had at 3 years of age. We observed no associations when the child was 5 years old.

However, in another study that included mothers and children from five birth cohorts, including MoBa, the authors found that cell phone use during pregnancy was related to a higher risk for the child to have hyperactivity/inattention problems at 5 years.

Personality, parenting style and other factors

Still, high cell phone use for the Norwegian women was related to a lower risk of emotional problems at 5 years. As in our study, the interpretation of such results is unclear. Mainly due to the small RF-EMF exposure that reached the fetus when the mother is using the phone while pregnant and due to other unmeasured factors that can “mask” the findings, such as maternal depression or anxiety, parenting style and maternal personality.

We assumed that extrovert women would talk more (using their cell phones more) and this can help their child to advance their communication skills. The “International Personality Item Pool” questionnaire assessed the mother’s extrovert personality. Even after taking into account maternal extroversion, cell phone use in pregnancy was not found to be harmful for the child’s neurodevelopment.

It seems that a social and family background that is beneficial for the child’s language and motor skills development, rather than parental cell phone use in itself, might cause the observed effects.

A changing world

There are still large gaps of knowledge on the effects of EMF-RF exposure to human health. By the time our study was conducted cell phone use was widespread. During the recruitment period (2001 – 2009), cell phone use increased from 68% to 99%.

Cell-phone technology has changed tremendously since 2009, with the major milestone of smart phone use. Smart phones and other smart devices have completely changed the way we use cell phones, including frequency of use, type of use and starting age of use.

Even though we cannot be absolutely sure if we could observe the same results if the study was conducted now and had included the widespread use of smart phones, the physical exposure to EMF-RF has not changed that much and we believe that our results also have validity for the present situation.