Maternal dental radiography during pregnancy is not associated with term low birth weight

Complete text of publication follows. 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 2 year study conducted at a midwifery hospital in Rafsanjan, IR Iran are reported. Methods: Four hundred seventy-five singleton infants with gestational periods of 37-44 wk born between 2006 and 2007 at the Niknafs Teaching Hospital affiliated with Rafsanjan University of Medical Sciences and met the inclusion criteria were enrolled in the study. Demographic data and clinical findings at birth including gestation 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, 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. 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.