Fetal tobacco syndrome and perinatal outcome

The aim of this study was to evaluate perinatal outcome in newborns of mothers who are smokers.

The study included 87 pregnant women with a single pregnancy in the cephalic position, 64 of them nonsmokers (group 1), 13 who smoked 5-20 cigarettes per day (group 2) and 10 who smoked more than 20 cigarettes per day (group 3). Maternal demographic variables and laboratory hemoglobin concentration, hematocrit and erythrocyte count in the last trimester were recorded. Perinatal outcome included type of delivery (vaginal or cesarean section), birth weight, occurrence of meconium in the amniotic fluid, 5-min Apgar score, umbilical arterial blood pH postpartum, sex of the newborn, need for treatment at a neonatal intensive care unit (NICU) and clinically and neurosonographically verified postpartum neurologic complications in the newborn.

A statistically significant correlation (p < 0.01) was found with the mean gestational age at delivery in all three groups of women, especially in those smoking >20 cigarettes per day, who had a higher incidence of premature deliveries. Maternal laboratory findings also differed significantly among the three groups of women, i.e. erythrocyte count (p < 0.01), hemoglobin concentration (p < 0.01) and hematocrit (p < 0.001). The rate of delivery by cesarean section was significantly higher in the groups of smokers, irrespective of the number of cigarettes per day (groups 2 and 3). Birth weight was lower by about 250 and 350 g (p < 0.001) in groups 2 and 3, respectively. Five-minute Apgar score and umbilical arterial blood pH were lower in group 3 as compared with groups 1 and 2 (p < 0.01). NICU treatment was required in more than 50% of infants born to group 3 mothers, in whom 70% of perinatal neurologic complications such as subependymal hemorrhage, periventricular hemorrhage, porencephalic cysts, intracranial hemorrhage and swallowing disturbance of the newborn were recorded (p < 0.001). The infants born to group 3 mothers had a longer and more difficult period of adaptation, thus often requiring an NICU stay.

Our study confirmed that pregnancy burdened with smoking, especially in the case of >20 cigarettes a day, is associated with a high risk due to the development of maternal anemia and fetal hypoxia and polyglobulia, which in turn result in a significantly poorer perinatal outcome in infants born to smoking mothers and compromised subsequent development of the child, as evidenced by the morphological substrates on the brain resulting from the fetal mechanism of defense against hypoxia. Clinically, there was no other (etiologic) reason for (chronic) fetal hypoxia; thus, the clinical substrate of fetal tobacco syndrome could be presumed to have developed consequentially to chronic smoking during pregnancy, as a preuterine factor of fetal hypoxia. Other gestational or gestation-related diseases (e.g., gestosis, diabetes) that may potentially cause nutritional and respiratory insufficiency of the placenta were ruled out.