Polychlorinated biphenyls in serum and time to pregnancy.

Polychlorinated biphenyls (PCBs) may affect the female reproductive system in both animals and humans. In Sweden, a main exposure source to PCBs is consumption of fatty fish from the Baltic Sea. From 165 female consumers of such fish (fishermen's sisters), information on time to pregnancy (TTP) and miscarriages was collected, blood was drawn, and serum was analyzed for 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), a biomarker for total PCB exposure. TTP and miscarriage data, as well as plasma CB-153 concentrations, for 121 fishermen's wives were available from previous studies. Thus, information on 286 women was available for investigation of whether a high exposure to PCB affects fertility negatively by increasing the TTP. The concentrations of CB-153 at the time of conception were estimated and trichotomized into low, medium, and high exposure groups. When we analyzed the joint data set of fishermen's wives and fishermen's sisters, a decrease rather than an increase in TTP was indicated for women in the medium (fecundability ratio 1.27 [95% confidence interval 0.89-1.82]) and high (fecundability ratio 1.42 [0.99-2.03]) exposure groups compared to those in the low exposure group. Similar results were found when we stratified on the original data set (fishermen's wives and fishermen's sisters) or childhood exposure. Women with miscarriages had lower estimated past CB-153 concentrations than women with live births. Our data provide no evidence of a hazardous effect associated with CB-153 concentration in the exposure range assessed. The exposure levels found in the fishermen's families, although high compared to that in the general Swedish population, may not be high enough to negatively affect fertility.