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2017 Conference

Abstract Number: 109 | ID: 2017-109

In Utero Dioxin Exposure and Fertility of the Seveso Second Generation

Brenda Eskenazi(Center for Environmental Research and Children's Health, School of Public Health, University of California, United States, eskenazi@berkeley.edu), Stephen Rauch(Center for Environmental Research and Children's Health, School of Public Health, University of California, United States), Jennifer Ames(Center for Environmental Research and Children's Health, School of Public Health, University of California, United States), Paolo Mocarelli(Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Italy), Paolo Brambilla(Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Italy), Stefano Signorini(Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Italy), Marcella Warner(Center for Environmental Research and Children's Health, School of Public Health, University of California, United States)
Background/Aim: In animal studies, maternal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is associated with decreased fertility in offspring. The Seveso Women’s Health Study (SWHS) of women exposed to TCDD in 1976 is unique in that we measured TCDD blood levels near the time of the explosion. In 2014, we initiated the Seveso Second Generation Health Study. We aim to examine the relationship of in utero TCDD exposure with time to pregnancy (TTP) and infertility among SWHS daughters.
Methods: We asked SWHS children ≥ 18 years about their pregnancy history, including time to pregnancy and infertility. Of 225 daughters, 80 had attempted pregnancy. Of these, 66 had delivered a livebirth not associated with contraceptive failure and 4 reported still trying unsuccessfully after 12 or more months. We defined in utero TCDD exposure as: 1) initial maternal serum TCDD concentration and 2) TCDD estimated at pregnancy. We examined the relation of in utero TCDD to TTP (parameterized as the monthly probability of conception within the first 12 months of trying) and to infertility (defined as conception after at least 12 months of trying). We modelled fecundability with discrete-time Cox proportional hazards regression and fertility with logistic regression.
Results: Women averaged 30.0 (±3.5) years at the time of attempting pregnancy. Median TTP was 2 months and 15.7% reported taking 12 or more months to conceive. A 10-fold increase in initial maternal TCDD was non-significantly associated with longer TTP (adjusted fecundability odds ratio = 0.61; 95%CI: 0.32, 1.18) and increased odds of infertility (adjusted odds ratio= 1.38; 95%CI: 0.36, 5.36). Results for TCDD estimated at pregnancy will be presented.
Conclusions: These results are consistent with animal studies and suggest in utero TCDD exposure may alter fertility in female offspring. However, sample size of pregnancies is lower than expected given the age of the female population.