UC Irvine

Background

For 15 months in 1981-1982, the commercial milk supply on the Hawaiian island of Oahu was contaminated with heptachlor epoxide, a metabolite of the insecticide heptachlor, resulting in gestational and/or lactational exposure to offspring of women who drank cow milk during that period.

Objective

To determine whether gestational and lactational exposure to heptachlor epoxide alters reproductive function and age at puberty in men or women.

Methods

457 participants were recruited from a prior high school enrollment sampling frame of 20,000 adults born during 1981-1982 who lived on Oahu since at least first grade. Number of glasses of cow milk consumed weekly by the mother during the participant's gestation was used as a surrogate measure of heptachlor epoxide exposure. Reproductive function measures included semen analyses; reproductive hormones or their metabolites in daily urine specimens for one menstrual cycle; serum reproductive hormone levels in both sexes; and reported ages of onset for pubertal milestones.

Results

We observed no strong associations of heptachlor epoxide exposure during gestation and lactation with reproductive endpoints. In females, heptachlor epoxide exposure was associated with longer luteal phase length and slower drop in the ratio of estradiol to progesterone metabolites after ovulation. In males, heptachlor epoxide exposure was weakly associated with higher serum follicle stimulating hormone and luteinizing hormone concentrations, but no dose-response relationship was apparent.

Conclusions

The results provide limited evidence that gestational and lactational exposure to heptachlor epoxide, due to milk contamination on Oahu in 1981-1982, resulted in clinically significant disturbances of reproductive function in men or women.