The Human Health Impact of Agent Orange

Reproductive Impacts

The issue of whether or not Dioxin causes birth defects in humans is still debated. What is clear, however, is Dioxin causes birth defects in animal studies, across all species studied. The herbicide 2,4-D has also been shown to be teratogenic in some studies, meaning it causes birth defects. Scientists hesitate to extrapolate these animal studies to epidemiological studies on humans.   

The March of Dimes estimates that six percent of live births worldwide result in a child born with a major birth defect that is either genetic or partially genetic in nature, including those that may be caused by exposure to toxic chemicals. Some birth defects may not be evident until several years after the child’s birth.

Any understanding of birth defects, in order to be extrapolated in any meaningful way, requires statistically significant quantities and the examination of a large exposed population. In addition, most epidemiological studies only focus on the offspring of exposed men, which produces less understanding about how Dioxin impacts reproduction outcomes in women. As a result, epidemiological studies on humans are challenging. 

Do Duc Diu, 58, tries to prevent daughter Do Thi Hang, 19, with congenital brain seizures, from injuring herself. Photo: Kuri Takashsashi, Chicago Tribune.

As progress in epigenetics is made, we begin to understand more about how chemicals, such as Dioxin, can influence how genes are signaled to turn on or off during fetal development. 

The U.S. National Academy of Science, Engineering and Medicine has reviewed the studies on the impacts of Dioxin and herbicides on birth defects and found inadequate or insufficient evidence of correlation between the two. It remains unclear if Dioxin can cause birth defects in exposed U.S. Veterans other than spina bifida. Currently, spina bifida in children born to male veterans is the only recognized condition that is eligible for compensation by the VA. But in children of U.S. female veterans, there is an added layer of complexity.

The VA does recognize a wide range of birth defects as connected to their service, but do not attribute it to Agent Orange exposure, or Dioxin specifically. Female veterans have to prove that their child’s birth defects have no known cause and that they themselves have no family history of any such conditions in order to be eligible for benefits. With only approximately 8,000 female veterans, the number of children receiving support from the VA is very small. 

“Vietnam is home to a disproportionately large number of disabled children – including many affected by exposure to chemicals left over from the spraying of Agent Orange.”
– Frank Susa, U.S. Fund for UNICEF, 2008.

While the U.S. Institute of Medicine originally attributed only spina bifida to paternal exposure to Dioxin, Vietnamese researchers have been studying the impacts of Agent Orange since the war and have found an increased risk of abnormal birth outcomes, including infertility, miscarriages, stillbirths, and birth defects via both paternal and maternal exposure. Among the birth defects found were spina bifida, hydrocephaly, malformations of the extremities, musculature issues, developmental disabilities, congenital heart defects, and cleft-palate. 

Table Source: Le Ke Son and Charles Bailey, From Enemies to Partners: Vietnam, the U.S. and Agent Orange.

Dang Hong Nhut stands over the crib of a young child with hydrocephalus in Bien Hoa. Mrs. Nhut was herself impacted by Agent Orange. She fought numerous cancers and had 3 miscarriages before a stillbirth in her fifth month of pregnancy. Her unborn son was severely disabled. She dedicated her life to helping children impacted by Agent Orange and died in 2018.

Vietnamese researchers have also found higher rates of birth defects in the grandchildren of the wartime exposed population.

The conditions of these children are believed to be associated with their parent or grandparent’s exposure to Agent Orange-Dioxin during the war. Today there are indeed high rates of children, young people, and adults with mobility, speech, and cognitive disabilities at varying levels of severity in the most heavily affected regions of Vietnam. Many are children who are unable to attend school are unemployable and in need of round-the-clock care. These affected populations face the greatest social and economic challenges.

Stills from “The Last Ghost of War” (2008), by dir. Janet Gardner. More information.

The Second Generation.
Photo: James Nachtwey