PATERNAL DIOXIN, PRETERM BIRTH, INTRAUTERINE GROWTH-RETARDATION, AND INFANT DEATH

We studied paternal exposure to Agent Orange and its dioxin contaminan t (2,3,7,8 tetrachlorodibenzo-p-dioxin) and preterm birth, intrauterin e growth retardation, or infant death in veterans of Operation Ranch H and, the unit responsible for spraying herbicides during the Vietnam w ar. A Comparison group of Air Force veterans who served in Southeast A sia during the same time period and who were not occupationally expose d to herbicides was included. We studied children conceived during or after the father's service in Southeast Asia and based exposure on pat ernal dioxin measured in 1987 or 1992 extrapolated to the time of conc eption of the child. We assigned each child to one of four exposure ca tegories: Comparison and three Ranch Hand categories (Background, Low, High). Children in the High (relative risk = 1.3) and Background (rel ative risk = 1.4) categories were at increased risk of preterm birth. The risk of intrauterine growth retardation was not increased in any e xposure category. The risk of infant death was increased in all Ranch Hand children, with the greatest increases in the High (relative risk = 4.5) and Background (relative risk = 3.2) categories. These patterns indicate that the increases in the relative risk of preterm birth and infant death may not be related to paternal dioxin level.