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Maternal DDT and DDE Exposure and Time to Pregnancy

Harley, K*; Marks, A*; Bradman, A*; Barr, D; Eskenazi, B*

doi: 10.1097/01.ede.0000276840.47158.f5

*University of California, Berkeley, United States; and †Centers for Disease Control and Prevention, United States.


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To examine the association of maternal exposure to DDT and its breakdown product, DDE, with time to pregnancy (TTP) and clinical infertility.

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Materials and Methods:

The study population comprised 293 women participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a cohort study of low-income, pregnant, predominantly Mexican women living in an agricultural region of California. We have shown previously that this population has considerably higher levels of p,p′-DDT and p,p′-DDE than the general U.S. population.

Analyses were restricted to women with DDT and DDE measurements who were not using contraception when they became pregnant. Maternal o,p′-DDT, p,p′-DDT and p,p′-DDE levels were measured in maternal serum collected during pregnancy or at delivery and analyzed by ID-high-resolution mass spectrometry. TPP was defined as the number of months to become pregnant, censored at 13 months. Clinical infertility was defined as 12 months of intercourse without contraception before becoming pregnant. We analyzed the association of TTP with log10, lipid-adjusted DDT and DDE as continuous variables using discrete-time Cox proportional hazards models, to obtain fecundability odds ratios (fOR). We analyzed the association with clinical infertility using logistic regression, to obtain odds ratios (OR) for infertility. All analyzes were adjusted for covariates.

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Median TTP was 3 months (range: 0–180 months). No association was found between o,p′-DDT, p,p′-DDT, and p,p′-DDE and TTP or clinical infertility. However, maternal work in agriculture in the months immediately preceding conception was associated with increased TTP (adjusted fOR = 0.60, P = 0.001) and increased odds of infertility (adjusted OR = 2.8, P = 0.01).

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Maternal exposure to DDT and DDE do not appear to be associated with fertility in this population. Further analysis of the association between maternal agriculture work and fertility will be presented.

© 2007 Lippincott Williams & Wilkins, Inc.