DDT and DDE exposure in mothers and time to pregnancy in daughters

Reproductive-tract anomalies after administration of the potent oestrogen, diethylstilboestrol, in pregnant women raised concerns about the reproductive effects of exposure to weakly oestrogenic environmental contaminants such as bis[4-chlorophenyl]-1,1,1-trichloroethane (p,p′-DDT) or its metabolites, such as bis[4-chlorophenyl]-1,1-dichloroethene (p,p′-DDE). The authors measured p,p′-DDT and p,p′-DDE in preserved maternal serum samples drawn 1-3 days after delivery between 1960 and 1963. We recorded time to pregnancy in 289 eldest daughters 28-31 years later. Daughters' probability of pregnancy fell by 32% per 10 Âµg/L p,p′-DDT in maternal serum (95% CI 11-48). By contrast, the probability of pregnancy increased 16% per 10 Âµg/L p,p′-DDE (6-27). The decreased fecundability associated with prenatal p,p′-DDT remains unexplained. The authors speculate that the antiandrogenic activity of p,p′-DDE may mitigate harmful androgen effects on the ovary during gestation or early life.