SMJ Mortazavi - Associate Professor of Medical Physics, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran ۲. The Center for Radiation Research, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
K Raygan Shirazi - Associate Professor of Medical Physics, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran ۲. The Center for Radiation Research, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
F Aminzadeh - Assistant Professor of Gynecology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
A Manshouri - Assistant Professor of Gynecology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran

Objective: In a report published in JAMA in 2004, Hujoel and colleagues indicated that maternal dental radiography during pregnancy may be associated with term low birth weight. Interestingly, they concluded that dental radiographies cause measurable radiation doses to the hypothalamus-pituitary-thyroid axis and the radiation effects on this axis is the reason for term low birth weight. On the other hand, low birth weight is the second leading cause of infant death. In this paper the results obtained in a 4 year study are reported. Methods: Nine hundred sixteen singleton infants with gestational ages of 37-42 weeks born between March 2006 and March 2008 at 2 different infant screening centers who met the inclusion criteria were enrolled in the study (475 infants were from the 1st center and 475 from the 2nd center). Demographic data and clinical findings at birth including gestational age, sex of infant, birth order, season of birth, maternal age, and maternal education were collected from maternal and newborn hospital records and by interviews with parents. Maternal history of exposure to common sources of man-made ionizing and non-ionizing (exposure to radiations emitted by mobile phones, CRTs, cordless phones) radiation before and during pregnancy were carefully recorded. Results: Among the 475 infants who were studied in the 1st center, there were only 15 cases with a history of maternal dental radiography during pregnancy. The average newborn infants' birth weight in non-exposed and exposed (maternal dental radiography during pregnancy) groups were 3166.69 ±481.31 g and 3118.67±341.42 g respectively. This difference was not statistically significant. In the 2nd center, among the 441 infants who were studied, there were 31 cases with a history of maternal dental radiography during pregnancy. The average newborn infants' birth weight in non-exposed and exposed (maternal dental radiography during pregnancy) groups were 3110.08 ±511.05 g and 2859.17±337.79 g respectively. Conclusions: In this study, low birth weight was not associated with maternal dental radiography during pregnancy. These results are generally inconsistent with those reported by Hujoel and colleagues.