Objective: To study the possible involvement of lead and cadmium in mechanisms of preterm labor.
Method: Estimations of lead and cadmium in blood, myometrium and placenta of Swedish and Polish women in preterm labor (n = 17) or delivered at term (n = 13).
Result: There was a positive correlation between pregnancy week and content of lead in blood. The mean blood concentration of cadmium in preterm delivered women, 2.0 micrograms/l, was significantly higher than that in term delivered patients, 0.6 microgram/l. In Polish patients the concentration of lead in blood, 37.9 micrograms/l, was higher than that in Swedish women of 11.2 micrograms/l. Cadmium concentrations in myometrium and placenta of Polish women, 0.2 and 0.3 microgram/g, respectively, were also significantly higher than the corresponding concentrations in Swedish patients, 0.04 and 0.1 microgram/g and this difference remained when only nonsmokers were compared. Smokers and nonsmokers did not have significantly different cadmium levels.
Conclusion: These results do not support the concept of lead causing increased myometrial activity in preterm labor, but indicate a higher uptake of lead and cadmium of Polish than of Swedish women. Further investigations are warranted to delineate the importance of the elevated concentration of cadmium in the blood of women with preterm labor.