| Long-Term Effects of Polychlorinated Biphenyls and Dioxins on Pregnancy Outcomes in Women Affected by the Yusho Incident Kiyomi Tsukimori,1,* Shoji Tokunaga,2,* Satoko Shibata,3 Hiroshi Uchi,3 Daisuke Nakayama,4 Tadayuki Ishimaru,4 Hitoo Nakano,1 Norio Wake,1 Takesumi Yoshimura,5 and Masutaka Furue3 1Department of Obstetrics and Gynecology, 2Department of Preventive Medicine, and 3Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; 4Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; 5Fukuoka Institute of Health and Environmental Science, Fukuoka, Japan Abstract
Background: Maternal exposure to polychlorinated biphenyls (PCBs) is associated with increased proportions of spontaneous abortion and stillbirth in animal studies. In Japan in 1968, accidental human exposure to rice oil contaminated with PCBs and other dioxin-related compounds, such as polychlorinated dibenzofurans (PCDFs) , led to the development of what was later referred to as Yusho oil disease. Objective: The aim of this study was to investigate the association of maternal PCB and dioxin exposure with adverse pregnancy outcomes in Yusho women. Methods: In 2004, we interviewed 214 Yusho women (512 pregnancies) about their pregnancy outcomes over the past 36 years. Pregnancy outcomes included induced abortion, spontaneous abortion, preterm delivery, and pregnancy loss. Results: In pregnancy years 1968–1977 (within the first 10 years after exposure) , the proportions of induced abortion [odds ratio adjusted for age at delivery (ORadj) = 5.93 ; 95% confidence interval (CI) , 2.21–15.91 ; two-tailed p < 0.001) and preterm delivery (ORadj = 5.70 ; 95% CI, 1.17–27.79 ; p =0.03) were significantly increased compared with the proportions in pregnancy years 1958–1967 (10 years before the incident) . Spontaneous abortion (ORadj = 2.09 ; 95% CI, 0.84–5.18) , and pregnancy loss (ORadj = 2.11 ; 95% CI, 0.92–4.87) were more frequent (OR = 2.18 ; 95% CI, 1.02–4.66) , but these were not significant (p =0.11 and p =0.08, respectively) in pregnancy years 1968–1977. We found no significant increases in the proportions of these adverse pregnancy outcomes in pregnancies occurring during 1978–1987 or 1988–2003 compared with those in pregnancies before 1968. Conclusion: High levels of PCB/PCDF exposure had some adverse effects on pregnancy outcome in Yusho women. Key words: dioxin, environmental exposure, pregnancy loss, preterm delivery, spontaneous abortion, Yusho. Environ Health Perspect 116:626–630 (2008) . doi:10.1289/ehp.10686 available via http://dx.doi.org/ [Online 6 February 2008]
Address correspondence to K. Tsukimori, Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan. Telephone: 81-92-642-5395. Fax: 81-92-642-5414. E-mail: tsuki@med.kyushu-u.ac.jp *These authors contributed equally to this work. This study was supported in part by a Grant-in-Aid for scientific research from the Ministry of Health, Labour and Welfare, Japan. The authors declare they have no competing financial interests. Received 18 July 2007 ; accepted 4 February 2008.
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