Chronic effects of maternal smoking on pulse waves in the fetal aorta

Objective.?In order to evaluate the impact of maternal smoking on arterial stiffness in utero, pulse wave characteristics in the fetal aorta were investigated. A prospective clinical study was made of 34 smoking and 34 non-smoking healthy volunteers with uncomplicated pregnancies at 31–40 weeks of gestation.

Methods.?The mechanical properties of the fetal thoracic aorta were assessed by an ultrasonic phase-locking echo-tracking system. For each fetus with a smoking mother, a non-smoking control matched for gestational and maternal age was monitored. Women with later appearing pregnancy complications were excluded. Pulse wave velocity (PWV), maximum diameter in systole (Ds), end-diastolic diameter (Dd), pulse amplitude (ΔD), and maximum incremental velocity (MIV) in the fetal aorta were measured and analyzed in relation to maternal smoking and gestational age.

Results.?Results were computed on fetuses of 32 smokers and 30 non-smokers. PWV increased with gestational age in smokers (corr. coeff. 0.49, p < 0.006) but not in non-smokers (corr. coeff. ?0.12). MIV did not change in smokers (corr. coeff. ?0.15) but increased in non-smokers (corr. coeff. 0.40, p < 0.03). Differences in regression lines between the groups regarding PWV and MIV were significant (p < 0.02 for both).

Conclusions.?Maternal smoking seems to promote the stiffening of the fetal aorta during gestation.