The influence of 2,2',4,4',5,5'-hexachlorobiphenyl on the placental blood flow in guinea pigs at a late stage of gestation.

Three groups of primaparous pregnant guinea pigs were fed once daily with a total of either 0 (control group, n = 9), 3 (n = 8), or 30 mg (n = 9) of 2,2',4,4',5,5'-hexachlorobiphenyl (HCB) starting at Day 45 of gestation to evaluate the effects of HCB on placental perfusion. The guinea pigs were separated into their groups randomly. At Day 63 of gestation the organ blood flow was determined with microsphere technique in the awake animal. The results show a statistically significant decrease in the placental blood flow and an increase in the pulmonary blood flow in the animals fed with 30 mg HCB compared to the control groups. A higher incidence of resorptions in fetuses is shown in both treatment groups compared to the control group. It is concluded that ecologically relevant doses of polychlorinated biphenyls might cause a deterioration in the placental function by reducing its blood flow.