RESUMEN
45 pregnant women married to heavy smokers and exposed for at least 2 hours/day were studied at 38-40 weeks of gestational age. Another 20 pregnant women of the same gestational age and not exposed to tobacco smoke, were studied as control. Maternal and fetal serum cotinine levels were assayed. The S/D ratio was determined by uterine and umbilical Doppler velocimetry wave-form analysis. The maternal serum cotinine levels were significantly higher in passive smokers [5.5 +/- 2.7 ng/ml] than nonsmokers [2.4 +/- 1.5 ng/ml] [P <0.001]. The fetal serum cotinine levels were also significantly higher in passive smokers than nonsmokers [2.14 +/- 1.3 and 0.79 +/- 0.3 ng/ml] respectively [P <0.001]. The S/D in passive smokers [2.5 +/- 0.8 and 2.7 +/- 0.9] was significantly higher than in nonsmokers [2.1 +/- 0.2 and 2.2 +/- 0.6] [P <0.01]. The elevated cotinine levels could be significantly correlated with the elevated S/D ratio of the uterine and umbilical arteries. This study strengthens the link between passive smoking and the adverse effects on the utero-placental hemodynamics and elucidates the value of cotinine as a monitor of passive exposure to tobacco smoke