Polybrominated biphenyls and fetal mortality in Michigan.

The contamination of the Michigan food supply by polybrominated biphenyls (PBBs) in the mid-1970s appears to have had little or no impact on fetal mortality. Comparison of fetal death rates among residents of Lower Peninsula counties with a high percentage of quarantined farms and among residents of Upper Peninsula counties with no quarantined farms reveals no important differences in rates or trends after the contamination. Since counts of early spontaneous abortions are lacking, a complete assessment of the possible impact on reproductive outcome cannot be made.