PCBs In Great Lakes Fish Don't Cause Fetal Loss, Study Finds

BUFFALO, N.Y. -- Researchers from the University at Buffalo have found no link between consumption of PCB-contaminated sport fish and a history of spontaneous fetal death or spontaneous abortion in humans, despite evidence of fetal harm in other mammals from PCB exposure.

Their study of live-birth certificates from 1,820 women who gave birth from 1986-91 and had a history of eating fish from Lake Ontario showed no relationship between consumption of lake-caught fish and greater risk of recognized spontaneous fetal death at any level of exposure. Chemical contamination of wildlife in Lake Ontario is estimated to be twice that of the other Great Lakes.

In addition, women at the highest level of consumption who had at least two pregnancies prior to the birth-certificate review showed a slight reduction in risk.

Results of the study were published in a recent issue of Environmental Health Perspectives, the journal of the National Institute of Environmental Health Services.

Pauline Mendola, Ph.D., UB research instructor of social and preventive medicine and lead author on the study, said the results were surprising.

"I thought we were going to see some evidence of risk," she noted. "The animal literature is pretty strong on this issue. There tends to be a lot of variation among adult animals in various species in response to PCBs. Some mammals are relatively resistant and some are very sensitive. But fetal toxicity seems to be much more sensitive and consistent across species."

The author cites several reasons why this investigation may have found no adverse outcomes from eating contaminated fish, including the possibility that PCBs affect human reproduction in ways other than causing spontaneous fetal death. The research group is currently studying the relationship of consumption of PCB-contaminated fish and female fertility, as well as other potential associations.

Mendola said the slight risk reduction observed in one group of women probably was not due to the fish.

"Contaminated fish should not be protective, " she stated. "Some other mechanism probably is at work, and we are investigating that further. Right now, about all we can say is that nothing dramatic is happening to increase the risk of spontaneous fetal death as a result of eating these fish."

The women in the study are a sub-group of the New York State Angler Cohort -- 11,431 anglers and their families who are enrolled in a UB-led investigation of the health effects of eating Lake Ontario sport fish. Sport-fish consumption has been estimated to deliver a dose of PCBs 4,300 times greater than the exposure from air or drinking water.

Exposure to PCBs has been associated with spontaneous fetal death or resorption of the fetus in rats, minks, rhesus monkeys and guinea pigs, and with significantly smaller litters in rabbits and swine. Consequently, people who eat Great Lakes fish also are considered at potential risk for developing reproductive problems.

Mendola said little research has been conducted on the relationship of PCB exposure and reproductive health in humans. The current study examined specifically the association between Lake Ontario fish consumption and history of spontaneous fetal death among fertile women.

Data on fish consumption were gleaned from questionnaires completed by the participants. Information on history of spontaneous fetal deaths was derived from birth certificates, which include the mother's full reproductive history. All women in the study were fertile with at least one pregnancy prior to the birth-certificate review.

Results showed no relationship between a history of spontaneous fetal death and four measures of sport fish consumption: lifetime PCB exposure, based on amount of each Lake Ontario species eaten and estimate of PCB levels in each species; years of Lake Ontario fish consumption; kilograms of Lake Ontario sport fish consumed in 1990-91, and lifetime estimate of kilograms eaten.

UB researchers Germaine M. Buck, Ph.D., John Vena, Ph.D., and Maria Zielezny, Ph.D., all from the Department of Social and Preventive Medicine, also participated in the study, along with Lowell E. Sever, Ph.D., from the Battelle Centers for Public Health Research and Evaluation in Seattle, Wash.

The research was funded in part by the Great Lakes Protection Fund.