Influence of maternal tobacco smoking during pregnancy on uterine, umbilical and fetal cerebral artery blood flows

Background: Cigarette smoking during pregnancy is a major cause of adverse perinatal outcome but effects on critical fetal and maternal circulations remain unclear. Aims: To determine (1) the influence of habitual maternal cigarette smoking on blood flow velocities in uterine, umbilical and fetal middle cerebral arteries, and (2) the time-course of changes in these flows after smoking a cigarette. Subjects and methods: In 74 women who smoked and 69 non-smoking controls we measured Doppler blood flow velocity waveforms in the uterine, umbilical and fetal middle cerebral (MCA) arteries; smokers were divided into light (<10 cigarettes/day, 11=28) and heavy smokers (>10 cigarettes/day, n=45). Results: In the uterine artery there was no significant difference between the systolic/diastolic (S/D) ratio in smoking and non-smoking women; however, in smokers, a diastolic notch was more frequently observed in the uterine artery waveform than in controls (p<0.05), suggestive of a greater resistance in the uterine vasculature. In the umbilical artery, the S/D ratio was significantly greater in smokers than in non-smokers. In the fetal MCA, the S/D ratio was higher in heavy smokers than in light smokers (p<0.05) indicative of greater cerebrovascular resistance. There were no significant correlations between the interval between smoking the last cigarette and making the Doppler measurements and the S/D ratios in any of the vessels. Conclusion: Maternal cigarette smoking is associated with evidence of chronically increased resistances in the uterine, umbilical and fetal middle cerebral arteries. (C) 2004 Elsevier Ireland Ltd. All rights reserved.