Children's exposure assessment of radiofrequency fields: comparison between spot and personal measurements

Radiofrequency (RF) fields are widely used and, while it is still unknown whether children are more vulnerable to this type of exposure, it is essential to explore their level of exposure in order to conduct adequate epidemiological studies. Personal measurements provide individualized information, but they are costly in terms of time and resources, especially in large epidemiological studies. Other approaches, such as estimation of time-weighted averages (TWAs) based on spot measurements could simplify the work.; The aims of this study were to assess RF exposure in the Spanish INMA birth cohort by spot measurements and by personal measurements in the settings where children tend to spend most of their time, i.e., homes, schools and parks; to identify the settings and sources that contribute most to that exposure; and to explore if exposure assessment based on spot measurements is a valid proxy for personal exposure.; When children were 8 years old, spot measurements were conducted in the principal settings of 104 participants: homes (104), schools and their playgrounds (26) and parks (79). At the same time, personal measurements were taken for a subsample of 50 children during 3 days. Exposure assessment based on personal and on spot measurements were compared both in terms of mean exposures and in exposure-dependent categories by means of Bland-Altman plots, Cohen's kappa and McNemar test.; Median exposure levels ranged from 29.73 (in children's bedrooms) to 200.10 μW/m; 2; (in school playgrounds) for spot measurements and were higher outdoors than indoors. Median personal exposure was 52.13 μW/m; 2; and median levels of assessments based on spot measurements ranged from 25.46 to 123.21 μW/m; 2; . Based on spot measurements, the sources that contributed most to the exposure were FM radio, mobile phone downlink and Digital Video Broadcasting-Terrestrial, while indoor and personal sources contributed very little (altogether <20%). Similar distribution was observed with personal measurements. There was a bias proportional to power density between personal measurements and estimates based on spot measurements, with the latter providing higher exposure estimates. Nevertheless, there were no systematic differences between those methodologies when classifying subjects into exposure categories. Personal measurements of total RF exposure showed low to moderate agreement with home and bedroom spot measurements and agreed better, though moderately, with TWA based on spot measurements in the main settings where children spend time (homes, schools and parks; Kappa = 0.46).; Exposure assessment based on spot measurements could be a feasible proxy to rank personal RF exposure in children population, providing that all relevant locations are being measured

Spatial and temporal variability of personal environmental exposure to radio frequency electromagnetic fields in children in Europe

Exposure to radiofrequency electromagnetic fields (RF-EMF) has rapidly increased and little is known about exposure levels in children. This study describes personal RF-EMF environmental exposure levels from handheld devices and fixed site transmitters in European children, the determinants of this, and the day-to-day and year-to-year repeatability of these exposure levels.; Personal environmental RF-EMF exposure (μW/m; 2; , power flux density) was measured in 529 children (ages 8-18 years) in Denmark, the Netherlands, Slovenia, Switzerland, and Spain using personal portable exposure meters for a period of up to three days between 2014 and 2016, and repeated in a subsample of 28 children one year later. The meters captured 16 frequency bands every 4 s and incorporated a GPS. Activity diaries and questionnaires were used to collect children's location, use of handheld devices, and presence of indoor RF-EMF sources. Six general frequency bands were defined: total, digital enhanced cordless telecommunications (DECT), television and radio antennas (broadcast), mobile phones (uplink), mobile phone base stations (downlink), and Wireless Fidelity (WiFi). We used adjusted mixed effects models with region random effects to estimate associations of handheld device use habits and indoor RF-EMF sources with personal RF-EMF exposure. Day-to-day and year-to-year repeatability of personal RF-EMF exposure were calculated through intraclass correlations (ICC).; Median total personal RF-EMF exposure was 75.5 μW/m; 2; . Downlink was the largest contributor to total exposure (median: 27.2 μW/m; 2; ) followed by broadcast (9.9 μW/m; 2; ). Exposure from uplink (4.7 μW/m; 2; ) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 μW/m; 2; ) than night (23.0 μW/m; 2; ), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 μW/m; 2; ) or traveling (171.3 μW/m; 2; ), and much lower at home (33.0 μW/m; 2; ) or in school (35.1 μW/m; 2; ). Children living in urban environments had higher exposure than children in rural environments. Older children and users of mobile phones had higher uplink exposure but not total exposure, compared to younger children and those that did not use mobile phones. Day-to-day repeatability was moderate to high for most of the general frequency bands (ICCs between 0.43 and 0.85), as well as for total, broadcast, and downlink for the year-to-year repeatability (ICCs between 0.49 and 0.80) in a small subsample.; The largest contributors to total personal environmental RF-EMF exposure were downlink and broadcast, and these exposures showed high repeatability. Urbanicity was the most important determinant of total exposure and mobile phone use was the most important determinant of uplink exposure. It is important to continue evaluating RF-EMF exposure in children as device use habits, exposure levels, and main contributing sources may change

Pre- and post-natal exposure to radiofrequency electromagnetic fields and neurodevelopment in children

With the recent evolution of mobile communication, there is a lack of understanding of increased radiofrequency (RF) exposure from these new technologies, especially among children. Little is known about the amount of RF exposure children experience day-to-day and its main sources. Furthermore, there is little understanding of RF dose during fetal life or RF dose to the brain during childhood. This thesis assessed environmental RF exposure and RF brain and body dose in children in several large, population-based cohort studies through personal exposure measurement studies and integrated exposure models. This thesis also evaluated whether maternal mobile phone use during pregnancy or RF dose to the brain in childhood was associated with neurodevelopmental outcomes, specifically, behavioral problems. In Europe, measured environmental RF in children and estimated dose to children’s brains was found to be far below recommended limits. Maternal mobile phone use during pregnancy was associated with hyperactivity/inattention problems in young children (ages 5-7) while RF dose to the brain during childhood was associated with behavioral problems, particularly in older children (ages 14-18). Uncontrolled confounding, reverse causality, and effects of mobile device use, apart from RF dose to the brain, could not be entirely excluded as possible explanations for these results. In the meantime, pregnant women could reduce RF exposure to the fetus by keeping mobile devices away from the belly, while children can reduce RF dose by limiting calls, limiting high resolution video streaming, or keeping mobile devices away from the body.Con la reciente evolución de la comunicación, existe una falta de comprensión del aumento de la exposición a la radiofrecuencia (RF) de estas nuevas tecnologías, especialmente entre los niños. Se sabe poco sobre la cantidad de exposición a RF que experimentan los niños día a día y sus principales fuentes. Además, hay poca comprensión de la cantidad de RF durante la vida fetal o la cantidad de RF en el cerebro durante la infancia. Esta tesis ha evaluado la exposición ambiental a RFs y la cantidad de RF en el cerebro y cuerpo en niños en varios estudios de cohorte de gran tamaño a través de estudios de medición de exposición personal y modelos de exposición integrados. Esta tesis también evaluó si el uso del teléfono móvil materno durante el embarazo o la cantidad de RF al cerebro en la infancia se asoció con problemas del desarrollo neurológico, específicamente, problemas de comportamiento. En Europa, la RF ambiental medida en niños y la cantidad estimada en el cerebro de los niños se encontraron muy por debajo de los límites recomendados. El uso del teléfono móvil materno durante el embarazo se asoció con problemas de hiperactividad/falta de atención en niños pequeños (entre 5 y 7 años) mientras que la cantidad de RF al cerebro durante la infancia se asoció con problemas de conducta, particularmente en niños mayores (14-18 años). Los factores de confusión no controlados, la causalidad inversa y los efectos del uso de dispositivos móviles, aparte de la cantidad de RF al cerebro, no podrían excluirse como posibles explicaciones para estos resultados. Además, las mujeres embarazadas podrían reducir la exposición a RF al feto manteniendo los dispositivos móviles alejados del estómago, mientras que los niños pueden reducir la cantidad de RF limitando las llamadas, limitando la transmisión de video de alta resolución o manteniendo los dispositivos móviles alejados del cuerpo

Pre- and post-natal exposure to radiofrequency electromagnetic fields and neurodevelopment in children

With the recent evolution of mobile communication, there is a lack of understanding of increased radiofrequency (RF) exposure from these new technologies, especially among children. Little is known about the amount of RF exposure children experience day-to-day and its main sources. Furthermore, there is little understanding of RF dose during fetal life or RF dose to the brain during childhood. This thesis assessed environmental RF exposure and RF brain and body dose in children in several large, population-based cohort studies through personal exposure measurement studies and integrated exposure models. This thesis also evaluated whether maternal mobile phone use during pregnancy or RF dose to the brain in childhood was associated with neurodevelopmental outcomes, specifically, behavioral problems. In Europe, measured environmental RF in children and estimated dose to children’s brains was found to be far below recommended limits. Maternal mobile phone use during pregnancy was associated with hyperactivity/inattention problems in young children (ages 5-7) while RF dose to the brain during childhood was associated with behavioral problems, particularly in older children (ages 14-18). Uncontrolled confounding, reverse causality, and effects of mobile device use, apart from RF dose to the brain, could not be entirely excluded as possible explanations for these results. In the meantime, pregnant women could reduce RF exposure to the fetus by keeping mobile devices away from the belly, while children can reduce RF dose by limiting calls, limiting high resolution video streaming, or keeping mobile devices away from the body.Con la reciente evolución de la comunicación, existe una falta de comprensión del aumento de la exposición a la radiofrecuencia (RF) de estas nuevas tecnologías, especialmente entre los niños. Se sabe poco sobre la cantidad de exposición a RF que experimentan los niños día a día y sus principales fuentes. Además, hay poca comprensión de la cantidad de RF durante la vida fetal o la cantidad de RF en el cerebro durante la infancia. Esta tesis ha evaluado la exposición ambiental a RFs y la cantidad de RF en el cerebro y cuerpo en niños en varios estudios de cohorte de gran tamaño a través de estudios de medición de exposición personal y modelos de exposición integrados. Esta tesis también evaluó si el uso del teléfono móvil materno durante el embarazo o la cantidad de RF al cerebro en la infancia se asoció con problemas del desarrollo neurológico, específicamente, problemas de comportamiento. En Europa, la RF ambiental medida en niños y la cantidad estimada en el cerebro de los niños se encontraron muy por debajo de los límites recomendados. El uso del teléfono móvil materno durante el embarazo se asoció con problemas de hiperactividad/falta de atención en niños pequeños (entre 5 y 7 años) mientras que la cantidad de RF al cerebro durante la infancia se asoció con problemas de conducta, particularmente en niños mayores (14-18 años). Los factores de confusión no controlados, la causalidad inversa y los efectos del uso de dispositivos móviles, aparte de la cantidad de RF al cerebro, no podrían excluirse como posibles explicaciones para estos resultados. Además, las mujeres embarazadas podrían reducir la exposición a RF al feto manteniendo los dispositivos móviles alejados del estómago, mientras que los niños pueden reducir la cantidad de RF limitando las llamadas, limitando la transmisión de video de alta resolución o manteniendo los dispositivos móviles alejados del cuerpo

Radiofrequency electromagnetic fields from mobile communication: Description of modeled dose in brain regions and the body in European children and adolescents

Background: Little is known about radiofrequency electromagnetic fields (RF) from mobile technology and resulting dose in young people. We describe modeled integrated RF dose in European children and adolescents combining own mobile device use and surrounding sources. Methods: Using an integrated RF model, we estimated the daily RF dose in the brain (whole-brain, cerebellum, frontal lobe, midbrain, occipital lobe, parietal lobe, temporal lobes) and the whole-body in 8358 children (ages 8-12) and adolescents (ages 14-18) from the Netherlands, Spain, and Switzerland during 2012-2016. The integrated model estimated RF dose from near-field sources (digital enhanced communication technology (DECT) phone, mobile phone, tablet, and laptop) and far-field sources (mobile phone base stations via 3D-radiowave modeling or RF measurements). Results: Adolescents were more frequent mobile phone users and experienced higher modeled RF doses in the whole-brain (median 330.4 mJ/kg/day) compared to children (median 81.8 mJ/kg/day). Children spent more time using tablets or laptops compared to adolescents, resulting in higher RF doses in the whole-body (median whole-body dose of 81.8 mJ/kg/day) compared to adolescents (41.9 mJ/kg/day). Among brain regions, temporal lobes received the highest RF dose (medians of 274.9 and 1786.5 mJ/kg/day in children and adolescents, respectively) followed by the frontal lobe. In most children and adolescents, calling on 2G networks was the main contributor to RF dose in the whole-brain (medians of 31.1 and 273.7 mJ/kg/day, respectively). Conclusion: This first large study of RF dose to the brain and body of children and adolescents shows that mobile phone calls on 2G networks are the main determinants of brain dose, especially in temporal and frontal lobes, whereas whole-body doses were mostly determined by tablet and laptop use. The modeling of RF doses provides valuable input to epidemiological research and to potential risk management regarding RF exposure in young people.GERoNiMO project: This work is supported by the European Union (grant 603794). HERMES project: This work is supported by the Swiss National Science Foundation (project number 138190). This research is also supported by the Swiss Research Foundation for Electricity and Mobile Communication (reference number 41). ABCD, The Netherlands: This work is supported by the Netherlands Organization for Health Research and Development (grant 2100.0076and within the programme Electromagnetic Fields and Health Research (grants 85600004 and 85800001). Generation R: The general design of the Generation R Study is made possible by financial support from the Erasmus Medical Center, Rotterdam, the Erasmus University Rotterdam, the Netherlands Organization for Health Research and Development (ZonMw (85500036)), the Netherlands Organization for Scientific Research (NWO), and the Ministry of Health, Welfare and Sport. Hanan El Marroun is supported by the European Union’s Horizon 2020 research and innovation program (no.733206 LifeCycle), Stichting Volksbond Rotterdam and the Dutch Brain Foundation (De Hersenstichting, project number GH2016.2.01) and the NARSAD Young Investigator Grant from the Brain & Behavior Research Foundation grant number 27853. The funding agencies had no role in the design or conduct of the study, collection, management, analyses or interpretation of the data, or preparation, review or approval of the manuscript or the decision to submit it for publication. INMA, Gipuzkoa: This study was funded by grants from Instituto de Salud Carlos III (FIS-PI13/02187), CIBERESP, Department of Health of the Basque Government (2015111065), and the Provincial Government of Gipuzkoa (DFG15/221) and annual agreements with the municipalities of the study area. INMA, Menorca: This study was funded by grants from Instituto de Salud Carlos III (Red INMA G03/176; CB06/02/0041; 97/0588; 00/0021-2; PI061756; PS0901958; PI14/00677 incl. FEDER funds), CIBERESP, Beca de la IV convocatoria de Ayudas a la Investigación en Enfermedades Neurodegenerativas de La Caixa, and EC Contract No. QLK4-CT-2000-00263. INMA, Sabadell: This study was funded by grants from Instituto de Salud Carlos III (Red INMA G03/176; CB06/02/0041; PI041436; PI081151 incl. FEDER funds; PI12/01890 incl. FEDER funds; CP13/00054 incl. FEDER funds, MS13/00054, CPII18/00018), CIBERESP, Generalitat de Catalunya-CIRIT 1999SGR 00241, Generalitat de Catalunya-AGAUR (2009 SGR 501, 2014 SGR 822), Fundació La marató de TV3 (090430), Spanish Ministry of Economy and Competitiveness (SAF2012-32991 incl. FEDER funds), Agence Nationale de Securite Sanitaire de l'Alimentation de l'Environnement et du Travail (1262C0010, EST-2016 RF-21), EU Commission (261357, 308333 and 603794). We also acknowledge support from the Spanish Ministry of Science and Innovation and State Research Agency through the “Centro de Excelencia Severo Ochoa 2019–2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program. INMA, Valencia: This study was funded by Grants from UE (FP7-ENV-2011 cod 282957 and HEALTH.2010.2.4.5-1), Spain: ISCIII (G03/176; FIS-FEDER: PI11/01007, PI11/02591, PI11/02038, PI13/1944, PI13/2032, PI14/00891, PI14/01687, PI16/1288, and PI17/00663; Miguel Servet-FEDER CP11/00178, CP15/00025, and CPII16/00051), and Generalitat Valenciana: FISABIO (UGP 15–230, UGP-15-244, and UGP-15-249)

Children's exposure assessment of radiofrequency fields: Comparison between spot and personal measurements

INTRODUCTION: Radiofrequency (RF) fields are widely used and, while it is still unknown whether children are more vulnerable to this type of exposure, it is essential to explore their level of exposure in order to conduct adequate epidemiological studies. Personal measurements provide individualized information, but they are costly in terms of time and resources, especially in large epidemiological studies. Other approaches, such as estimation of time-weighted averages (TWAs) based on spot measurements could simplify the work. OBJECTIVES: The aims of this study were to assess RF exposure in the Spanish INMA birth cohort by spot measurements and by personal measurements in the settings where children tend to spend most of their time, i.e., homes, schools and parks; to identify the settings and sources that contribute most to that exposure; and to explore if exposure assessment based on spot measurements is a valid proxy for personal exposure. METHODS: When children were 8 years old, spot measurements were conducted in the principal settings of 104 participants: homes (104), schools and their playgrounds (26) and parks (79). At the same time, personal measurements were taken for a subsample of 50 children during 3 days. Exposure assessment based on personal and on spot measurements were compared both in terms of mean exposures and in exposure-dependent categories by means of Bland-Altman plots, Cohen's kappa and McNemar test. RESULTS: Median exposure levels ranged from 29.73 (in children's bedrooms) to 200.10 μW/m2 (in school playgrounds) for spot measurements and were higher outdoors than indoors. Median personal exposure was 52.13 μW/m2 and median levels of assessments based on spot measurements ranged from 25.46 to 123.21 μW/m2. Based on spot measurements, the sources that contributed most to the exposure were FM radio, mobile phone downlink and Digital Video Broadcasting-Terrestrial, while indoor and personal sources contributed very little (altogether <20%). Similar distribution was observed with personal measurements. There was a bias proportional to power density between personal measurements and estimates based on spot measurements, with the latter providing higher exposure estimates. Nevertheless, there were no systematic differences between those methodologies when classifying subjects into exposure categories. Personal measurements of total RF exposure showed low to moderate agreement with home and bedroom spot measurements and agreed better, though moderately, with TWA based on spot measurements in the main settings where children spend time (homes, schools and parks; Kappa = 0.46). CONCLUSIONS: Exposure assessment based on spot measurements could be a feasible proxy to rank personal RF exposure in children population, providing that all relevant locations are being measured

Characterisation of exposure to non-ionising electromagnetic fields in the Spanish INMA birth cohort: study protocol

Background: Analysis of the association between exposure to electromagnetic fields of non-ionising radiation (EMF-NIR) and health in children and adolescents is hindered by the limited availability of data, mainly due to the difficulties on the exposure assessment. This study protocol describes the methodologies used for characterising exposure of children to EMF-NIR in the INMA (INfancia y Medio Ambiente- Environment and Childhood) Project, a prospective cohort study. Methods/Design: Indirect (proximity to emission sources, questionnaires on sources use and geospatial propagation models) and direct methods (spot and fixed longer-term measurements and personal measurements) were conducted in order to assess exposure levels of study participants aged between 7 and 18 years old. The methodology used varies depending on the frequency of the EMF-NIR and the environment (homes, schools and parks). Questionnaires assessed the use of sources contributing both to Extremely Low Frequency (ELF) and Radiofrequency (RF) exposure levels. Geospatial propagation models (NISMap) are implemented and validated for environmental outdoor sources of RFs using spot measurements. Spot and fixed longer-term ELF and RF measurements were done in the environments where children spend most of the time. Moreover, personal measurements were taken in order to assess individual exposure to RF. The exposure data are used to explore their relationships with proximity and/or use of EMF-NIR sources. Discussion: Characterisation of the EMF-NIR exposure by this combination of methods is intended to overcome problems encountered in other research. The assessment of exposure of INMA cohort children and adolescents living in different regions of Spain to the full frequency range of EMF-NIR extends the characterisation of environmental exposures in this cohort. Together with other data obtained in the project, on socioeconomic and family characteristics and development of the children and adolescents, this will enable to evaluate the complex interaction between health outcomes in children and adolescents and the various environmental factors that surround them.This study was funded by grants from the Spanish Instituto de Salud Carlos III Health Institute (PI13/02187 incl. FEDER funds, CP13/00054 incl. FEDER funds, MS13/00054), the councils of the study region of Gipuzkoa and the EU Commission (603794)

Estimated whole-brain and lobe-specific radiofrequency electromagnetic fields doses and brain volumes in preadolescents

OBJECTIVE: To assess the association between estimated whole-brain and lobe-specific radiofrequency electromagnetic fields (RF-EMF) doses, using an improved integrated RF-EMF exposure model, and brain volumes in preadolescents at 9-12 years old. METHODS: Cross-sectional analysis in preadolescents aged 9-12 years from the Generation R Study, a population-based birth cohort set up in Rotterdam, The Netherlands (n = 2592). An integrated exposure model was used to estimate whole-brain and lobe-specific RF-EMF doses (mJ/kg/day) from different RF-EMF sources including mobile and Digital Enhanced Cordless Telecommunications (DECT) phone calls, other mobile phone uses than calling, tablet use, laptop use, and far-field sources. Whole-brain and lobe-specific RF-EMF doses were estimated for all RF-EMF sources together (i.e. overall) and for three groups of RF-EMF sources that lead to a different pattern of RF-EMF exposure. Information on brain volumes was extracted from magnetic resonance imaging scans. RESULTS: Estimated overall whole-brain RF-EMF dose was 84.3 mJ/kg/day. The highest overall lobe-specific dose was estimated in the temporal lobe (307.1 mJ/kg/day). Whole-brain and lobe-specific RF-EMF doses from all RF-EMF sources together, from mobile and DECT phone calls, and from far-field sources were not associated with global, cortical, or subcortical brain volumes. However, a higher whole-brain RF-EMF dose from mobile phone use for internet browsing, e-mailing, and text messaging, tablet use, and laptop use while wirelessly connected to the internet was associated with a smaller caudate volume. CONCLUSIONS: Our results suggest that estimated whole-brain and lobe-specific RF-EMF doses were not related to brain volumes in preadolescents at 9-12 years old. Screen activities with mobile communication devices while wirelessly connected to the internet lead to low RF-EMF dose to the brain and our observed association may thus rather reflect effects of social or individual factors related to these specific uses of mobile communication devices. However, we cannot discard residual confounding, chance finding, or reverse causality. Further studies on mobile communication devices and their potential negative associations with brain development are warranted, regardless whether associations are due to RF-EMF exposure or to other factors related to their use

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

INTRODUCTION: Previous studies have reported associations between prenatal cell phone use and child behavioral problems, but findings have been inconsistent and based on retrospective assessment of cell phone use. This study aimed to assess this association in a multi-national analysis, using data from three cohorts with prospective data on prenatal cell phone use, together with previously published data from two cohorts with retrospectively collected cell phone use data. METHODS: We used individual participant 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). We categorized cell phone use into none, low, medium, and high, based on frequency of calls during pregnancy reported by the mothers. Child behavioral problems (reported by mothers using the Strengths and Difficulties Questionnaire or Child Behavior Checklist) were classified in the borderline/clinical and clinical ranges using validated cut-offs in children aged 5-7years. Cohort specific risk estimates were meta-analyzed. RESULTS: Overall, 38.8% of mothers, mostly from the Danish cohort, reported no cell phone use during pregnancy and these mothers were less likely to have a child with overall behavioral, hyperactivity/inattention or emotional problems. Evidence for a trend of increasing risk of child behavioral problems through the maternal cell phone use categories was observed for hyperactivity/inattention problems (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). This association was fairly consistent across cohorts and between cohorts with retrospectively and prospectively collected cell phone use data. CONCLUSIONS: Maternal cell phone use during pregnancy may be associated with an increased risk for behavioral problems, particularly hyperactivity/inattention problems, in the offspring. The interpretation of these results is unclear as uncontrolled confounding may influence both maternal cell phone use and child behavioral problems.This work was supported by the European Union: GERoNiMO project (grant 603794) and grants FP7-ENV-2011, 282957, HEALTH.2010.2.4.5-

Associations of maternal cell-phone use during pregnancy with pregnancy duration and fetal growth in 4 birth cohorts

Results from studies evaluating potential effects of prenatal exposure to radio-frequency electromagnetic fields from cell phones on birth outcomes have been inconsistent. Using data on 55,507 pregnant women and their children from Denmark (1996-2002), the Netherlands (2003-2004), Spain (2003-2008), and South Korea (2006-2011), we explored whether maternal cell-phone use was associated with pregnancy duration and fetal growth. On the basis of self-reported number of cell-phone calls per day, exposure was grouped as none, low (referent), intermediate, or high. We examined pregnancy duration (gestational age at birth, preterm/postterm birth), fetal growth (birth weight ratio, small/large size for gestational age), and birth weight variables (birth weight, low/high birth weight) and meta-analyzed cohort-specific estimates. The intermediate exposure group had a higher risk of giving birth at a lower gestational age (hazard ratio = 1.04, 95% confidence interval: 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. Maternal cell-phone use during pregnancy may be associated with shorter pregnancy duration and increased risk of preterm birth, but these results should be interpreted with caution, since they may reflect stress during pregnancy or other residual confounding rather than a direct effect of cell-phone exposure.The Generalized EMF Research Using Novel Methods (GERoNiMO) Project was supported by the European Union (grant 603794). The Amsterdam Born Children and Their Development Study (ABCD) was supported by the Netherlands Organization for Health Research and Development (grant 2100.0076) and the Electromagnetic Fields and Health Research program (grants 85600004 and 85800001). The Danish National Birth Cohort Study (DNBC) was supported by the Danish Epidemiology Science Centre, the Lundbeck Foundation (grant 195/04), the Egmont Foundation, the March of Dimes Birth Defect Foundation, the Augustinus Foundation, and the Medical Research Council (grant SSVF 0646). The Spanish Environment and Childhood Project (INMA) was supported by the European Union (grants FP7-ENV-2011, 282957, and HEALTH.2010.2.4.5-1); Instituto de Salud Carlos III (grants G03/176, CB06/02/0041, FIS-FEDER 03/1615, 04/1509, 04/1112, 04/1931, 05/1079, 05/1052, 06/1213, 07/0314, 09/02647, 11/01007, 11/02591, CP11/00178, FIS-PI06/0867, FIS-PS09/00090, FIS-PI041436, FIS-PI081151, FIS-PI042018, FIS-PI09/02311, FISPI13/1944, FIS-PI13/2429, FIS-PI14/0981, FIS-PI13/141687, CP13/00054 (including FEDER funds), and MS13/00054); the Conselleria de Sanitat Generalitat Valenciana; the Generalitat de Catalunya (grants CIRIT1999SGR and 00241); Obra Social Cajastur; the Universidad de Oviedo; the Department of Health of the Basque Government (grants 2005111093 and 2009111069); and the Provincial Government of Gipuzkoa (grants DFG06/004 and DFG08/001). The Korean Mothers and Children’s Environment Health Study (MOCEH) was supported by the National Institute of Environmental Research, the Ministry of the Environment, and the Information and Communication Technology (ICT) research and development program of the Ministry of Science and ICT (grants 2017-0-00961 and 2019-0-00102), South Korea