Is there an association between preconception paternal x-ray exposure and birth outcome? The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood.

Diagnostic x-rays are performed commonly on men of reproductive age, yet little is known about the potential effects of these x-rays on the future unborn children of such men. This study examines the possibility that preconception diagnostic x-ray studies of fathers may adversely effect their newborns. The authors used prospectively collected data from the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) for 7,678 birth records for women who gave birth in the County of Avon, England, in 1991-1992. Birth weight, gestational age, and fetal growth of infants whose fathers received diagnostic x-ray examinations likely to deliver significant gonadal doses within one year prior to conception were compared with infants whose fathers did not receive such x-rays. The mean birth weight of babies of exposed fathers was 3,358 g compared with a mean of 3,437 g in the unexposed group (p = 0.055). A similar difference was noted for intrauterine growth, 3,374 g exposed versus 3,437 g unexposed (p = 0.078). The downward trend in birth weight and fetal growth (birth weight adjusted for gestational age) persisted despite control for infants' sex and important parental variables such as age, height, race, education, occupational exposure, parity, and maternal smoking. Because medical x-rays are the largest controllable source of man-made ionizing radiation, more detailed study of the potential effect of paternal x-irradiation on progeny seems justified.