Acute effects of maternal smoking on fetal-placental-maternal system hemodynamics.
OBJECTIVE
To study acute hemodynamic alterations in the fetal-placental maternal system immediately after maternal exposure to nicotine.


METHODS
This is a noncontrolled experimental study involving 21 pregnant smoking women, randomly selected, with uncomplicated pregnancies and without risk factors for fetal heart disease. Patients underwent ultrasound and fetal echocardiography before and after smoking a cigarette. They were asked to abstain from smoking for 12 hours before the study. The mean nicotine content of the cigarettes used in the study was 0.5mg of nicotine and 6mg of carbon monoxide.


RESULTS
The average number of cigarettes smoked per a day prior to the study was 9.67. Gestational age ranged between 18 and 36 weeks. The mean maternal heart rate was elevated (P<0.001) as was the mean fetal heart rate (P=0.044). Maternal systolic blood pressure (P=0.004) and diastolic blood pressure (P=0.033) were also elevated after smoking. A decrease occurred in the systolic/diastolic ratio in the right uterine artery (P=0.014) and in the left uterine artery (P=0.039). The other hemodynamic variables remained unchanged.


CONCLUSIONS
Cigarette smoking can cause changes in physiologic variables of fetal-placental circulation, but it does not change fetal cardiac function, in the dose of nicotine and its components used in this study. The decrease in systolic/diastolic ratio in the uterine arteries is probably related to a dose-dependent nicotine pattern.
Müller
Janine Santos
JS
Instituto de Cardiologia do Rio Grande do Sul, Fundação Universitária de Cardiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Antunes
Marcelo
M
Behle
Ivo
I
Teixeira
Lucas
L
Zielinsky
Paulo
P
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D004452:Echocardiography / Q000379:methods; D005260:Female; D005865:Gestational Age; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D021041:Placental Circulation / Q000502:physiology*; D011247:Pregnancy; D012907:Smoking / Q000009:adverse effects* / Q000503:physiopathology; D016216:Ultrasonography, Prenatal / Q000379:methods