Menstrual effects among women exposed to polychlorinated biphenyls and dibenzofurans

Polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs), and dibenzo-dioxins (PCDDs) may affect the female reproductive system in humans. A mass poisoning occurred in Taiwan due to PCBs/PCDFs-contaminated cooking oil, and was called the Yucheng (oil-disease in Chinese). We aimed to determine whether Yucheng women were affected in their menstruation.

After the event, we followed the exposed individuals and an age-matched neighborhood reference group. Menstrual cycle characteristics and age at menarche were obtained by a telephone interview. We used multiple linear and logistic regression to examine the association between PCBs/PCDFs and menstrual cycle characteristics, after adjusting for confounding factors.

Totally 445 women responded satisfactorily and were included in the analyses of menstrual characteristics. Menstrual cycle irregularity and dysmenorrheal did not differ between Yucheng and referents. Yucheng women's menstrual cycles were 0.5 (95% CI: 0.0-0.5; p=0.03) days shorter than those of the referents. The Yucheng women with skin lesions caused by PCBs/PCDFs were more prominently affected, with the cycles 1.2 days shorter than the referents. Yucheng women exposed to PCBs/PCDFs at the premenacheal period had reduced cycle length (-0.7 day, 95% CI: -1.4 to 0.0; p=0.04) and longer days of menstrual flow (0.5 day, 95% CI: 0.0-1.0; p=0.04). Among those women who were exposed at an age of 5-9 years, menarche started slightly earlier with borderline significance.

Shorter menstrual cycle length and a longer duration of bleeding in each cycle were found among women previously exposed to PCBs/PCDFs. These effects were more obviously observed among those exposed at premenarcheal ages.