Objectives: This study assessed paternal occupational exposure to di(2-ethylhexyl)phthalate (DEHP) in association with reduced fertility.
Methods: Men working in three plants with DEHP exposure were studied retrospectively. Male and female employees and their partners were invited to participate if they had reported a pregnancy or an attempt to achieve a pregnancy. Postal questionnaires and telephone interviews were used to collect additional data from the men and women, respectively. Information on time to pregnancy was eligible for 326 pregnancies fathered by 193 men. Male exposure to DEHP during every month of their time to pregnancy was classified into one of three exposure categories. The exposure ranged from <0.1 to 2.1 mg/m3. The fathers of only four pregnancies had DEHP exposure of >0.5 mg/m3 during the time to pregnancy. The pregnancies of employed women with unexposed partners or pregnancies of employed men unexposed during the time to pregnancy formed the reference group.
Results: The fecundability ratio for time to pregnancy was 1.07 [95% confidence interval (95% CI) 0.84-1.35] for those with low exposure and 0.97 (95% CI 0.70-1.33) for the highly exposed after adjustment for the father's age, mother's age, and length of recall. When the analyses were restricted to first pregnancy, the fecundability ratio was 1.13 (95% Cl 0.83-1.56) for low exposure and 1.02 (95% CI 0.66-1.59) for high exposure.
Conclusions: Time to pregnancy is not prolonged among couples with paternal exposure to DEHP at a mean exposure level of <0.5 mg/m3.