Antepartum fetal and maternal carboxyhemoglobin and cotinine levels among cigarette smokers

The objective of this study was to examine the association of carboxyhemogl obin (COHb) and plasma cotinine levels among pregnant women who smoke cigar ettes and their fetuses. Fifteen pregnant women who smoked and their fetuse s undergoing cordocentesis had blood samples analysed simultaneously for CO Hb and cotinine. Linear regression was used to test for associations among study variables. Significant maternal-fetal associations were observed both with COHb (r=0.72, p=0.003) and with cotinine (r=0.96, p=0.003). Maternal cotinine levels were correlated with maternal and fetal COHb, levels (r=0.9 6, p=0.003; r=0.99, p=0.0003, respectively). Fetal cotinine levels were cor related with COHb in maternal and in fetal blood (r=0.81, p=0.0003; r=0.88, p<0.0001, respectively). The strong direct associations of maternal and fe tal levels of COHb and cotinine indicate that maternal COHb and cotinine me asurements may be interpreted as surrogates of fetal COHb levels. However, the specificity, ex vivo stability and ease of measurement of cotinine offe r advantages over using COHb in quantifying fetal CO exposure following mat ernal cigarette smoking.