Effects of exposure to tobacco smoke in pregnancies complicated by oligohydramnios and premature rupture of the membranes. I. Concentration of Cd and Pb in blood and Zn, Cu, Cd and Pb in amniotic fluid.

To assess the exposure to tobacco smoke in pregnant women with oligohydramnios, idiopathic or caused by premature rupture of the membranes (PROM), cotinine concentrations were measured, using enzyme-like immunosorbent assay (ELISA). In women with idiopathic oligohydramnios (22-31 weeks of gestation), serum cotinine concentration was 1010 +/- 445 micrograms/L which provides evidence that women of this group were heavy smokers. In these women, significantly higher Cd concentrations in blood and amniotic fluid were found as compared to other pregnant women. A positive correlation between Cd concentrations in blood and amniotic fluid was observed (PROM r = 0.784; p < 0.001; idiopathic oligohydramnios r = 0.7118; p < 0.02). In oligohydramnios cases of both types, Cd concentration in amniotic fluid was over two times and Pb concentration ten times lower than blood concentrations of these metals, whereas amniotic fluid Zn concentration was two times lower than that found earlier in women with normal pregnancy. In the group of women with idiopathic oligohydramnios who were mostly exposed to tobacco smoke, a considerably larger number of still births and new-borns with CNS disorders than in PROM cases, were observed. Zn deficiency at increased exposure to Cd and Pb could play a significant role in etiology of these abnormalities. A positive correlation was found between Zn and Cu concentrations (r = 0.862; p < 0.05) in PROM cases which indicates regular transport of trace metals to the fetal ovum. The condition of infants born to this group of women was much better, and prematurity was the only complication of pregnancy.