Time to pregnancy among the wives of men occupationally exposed to lead

We conducted a retrospective study on time to pregnancy among the wives of men biologically monitored for lead to assess whether paternal occupational exposure to inorganic lead is associated with decreased fertility. After t hree mailings, 554 (72.2%) wives of the monitored men participated. The fin al study population consisted of 502 couples who did not use contraception at the beginning of the pregnancy. We assessed lead exposure from blood lea d measurements and from questionnaires completed by the men. We calculated the relative fecundability density ratios with discrete proportional hazard s regression. The fecundability density ratios, adjusted for potential conf ounders, were 0.92 [95% confidence interval (95% CI) = 0.73-1.16], 0.89 (95 % CI = 0.66-1.20), 0.58 (95% CI = 0.33-0.96), and 0.83 (95% CI = 0.50-1.32) for blood lead categories 0.5-0.9, 1.0-1.4, 1.5-1.8, and greater than or e qual to 1.9 mu mol/L, respectively, as compared with <0.5 mu mol/L. The fin dings provide limited support for the hypothesis that paternal exposure to lead is associated with decreased fertility.