Résumé :
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[BDSP. Notice produite par INIST-CNRS lNnsyR0x. Diffusion soumise à autorisation]. Polychlorinated biphenyls (PCBs), once used widely in transformers and other applications, and 1,1 - dichloro-2,2-bis (p-chlorophenyl) ethylene (DDE), the main metabolite ofthe pesticide 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT), are hormonally active agents. Changes in menstrual cycle functioning associated with PCBs and DDE, and increased odds of spontaneous abortion associated with DDE, suggest that these compounds could affect fertility. The authors investigated the association between PCB and DDE exposure and time to pregnancy by using serum levels measured in 390 pregnant women in the Collaborative Perinatal Project enrolled at 12 study centers in the United States from 1959 to 1965. They estimated adjusted fecundability odds ratios by using Cox proportional hazards modeling for discrete time data. Compared with time to pregnancy for women in the lowest exposure category (PCBs5.00 mug/liter=0.65,95% confidence interval : 0.36,1.18) and DDE (fecundability odds ratio for DDE>60 mug/liter=0.65,95% confidence interval : 0.32,1.31). Overall, time to pregnancy increased with increasing serum PCB levels but was less suggestive of an association with DDE. Both trends were imprecise and attenuated when expressed on a lipid basis. Overall, evidence of an association between PCB or DDE exposure and time to pregnancy was weak and inconclusive.
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