Review of Recent Vietnamese Studies on the Carcinogenic and Teratogenic Effects of Phenoxy Herbicide Exposure

The methodology and results of several Vietnamese studies on the possible health effects of exposure to herbicides among the Vietnamese during the Second Indochina War are reviewed. The results of the studies appear to link either paternal or maternal exposure to herbicides to unfavorable outcomes of pregnancy. There is some evidence to suggest that the injury to reproduction diminishes over time. Two studies found statistically significant odds ratios of 4.6 and 12.0 for hydatidiform moles after exposure. One case-control study found a statistically significant odds ratio of 5.2 for liver cancer. Elevated odds ratios were also found for major externally detectable birth defects. Many of the detailed findings are in agreement with the results of animal experiments. Unfortunately, the Vietnamese do not have the resources to fully examine the health effects of phenoxy herbicides. It is our hope that recognition of the importance of the Vietnamese studies will lead to further work in this area.