Brenda Eskenazi, Ph.D.
Background: On July 10, 1976, an explosion occurred at an chemical manufacturing facility in Seveso, Italy. Approximately 30 kg of dioxin were released into the environment resulting in the highest exposure to 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) known in human residential populations. Eleven communities in the densely populated area between Milan and Lake Como were contaminated. Researchers at the University of California Berkeley, along with colleagues in Italy at the University Milano-Bicocca, initiated the Seveso Women's Health Study to determine whether there was an association between TCDD exposure and adverse reproductive health outcomes.
TCDD is considered to be one of, if not the most toxic man-made substance. It has been shown to cause cancer and disrupt multiple endocrine functions. TCDD is a by-product of several manufacturing processes such as paper production and pesticide formulation. Among its varied effects, TCDD has been shown to cause increased fetal loss and reduced birth weight in animal studies.
Advance: In the current study, the pregnancy outcomes of 510 women representing 888 total pregnancies were examined in relation to TCDD in serum samples collected from these women shortly after the explosion. Ninety-seven of the pregnancies ended in spontaneous abortions. There were no significant associations between TCDD exposure and spontaneous abortion, birth weight, or births that were small for gestational age. However, although not statistically significant, there were stronger associations for birth weight and small for gestational age among pregnancies that occurred within the first eight years after exposure.
Implication: This study reports the lack of a statistically significant association between maternal serum levels of TCDD and adverse birth outcomes in this cohort of women. However, the authors state "It remains possible that the effects of TCDD on birth outcomes are yet to be observed, because the most heavily exposed women were the youngest at follow-up and therefore are less likely to have yet had a post-explosion pregnancy." Additional epidemiologic studies are planned to further investigate this exposure.
Citation: Eskenazi B, Mocarelli P, Warner M, Chee WY, Gerthoux PM, Samuels S, Needham LL, Patterson DG Jr. Maternal serum dioxin levels and birth outcomes in women of Seveso, Italy. Environ Health Perspect. 2003 Jun;111(7):947-53.