PRE-AND POSTNATAL PHYSICAL GROWTH UP TO 2 YEARS OF AGE IN RELATIONSHIP TO THE MATERNAL SMOKING STATUS

Karatza A, Varvarigou A and Beratis NG

¹Pediatrics, Univ. Patras, Patras, Greece

Background: Maternal smoking during pregnancy causes intrauterine growth retardation (GR), but the extrauterine growth is not well known.
Objective: To compare the intra- and extra-uterine growth of children whose mothers smoked during pregnancy to that of nosmoking mothers' children, in relationship to the number of cigarettes smoked/d.
Design/Methods: Weight (W), length (L) and head circumference (HC) weremeasured in 256 (128 male) newborns of smoking mothers and 256 (128 male) control newborns of nonsmoking mothers. Children were reexamined at 1 and 2 ys. The anthropometric parameters were correlated to no of cigarettes smoked/d, and to cord blood a-fetoprotein and erythropoietin concentrations.
Results: Newborns of mothers who smoked 1-9 cigarettes/d had similar anthropometric parameters with the controls. Significant retardation in W, L and HC was present in the newborns whose mothers smoked 10-19 and 20 cigarettes/d. At 1 y, the children of smoking mothers were smaller than the controls (L<HC<W). At 2 ys, the L of children whose mothers smoked 20, 10-19 and 1-9 cigarettes/d was significantly smaller than in the controls (-3.9 cm, p=0.00001; -2.9 cm, p=0.0003; and -2.3,p=0.02, respectively). Also, the HC of the children whose mothers smoked 20 cigarettes/d was significantly smaller than in the controls (-1.4cm, p=0.000008), and of those whose mothers smoked 10-19 cigarettes (-0.9 cm, p=0.006) and 1-9 cigarettes (-0.9 cm, p=0.006). At 2 yrs, stepwise multilinear regression analysis showed that extrauterine retardation in L and HC was indepentently associated with maternal smoking (p<0.0001). At birth, there were strong negative correlations between no. of cigarettes smoked/d and the anthropometric parameters studied (p<0.001); at 1 yr, there were negative correlations of bordeline significance (p<0.05); and at 2 yrs, there was no correlation. Also, there was a significant negative correlation between growth and cord blood a-fetoprotein concentrations, whereas there was no correlation between growth and erythopoietin concentrations.
Conclusions: The findings suggest that:(1) there is a threshold of about 10 cigarettes/d beyond which intrauterine GR ensues; (2) W tends towards normality at 2 yrs; (3) L retardation deteriorates further during the first 2 yrs; (4) retardation of HC remains stable at 2 yrs; (5) at birth GR is negatively correlated to the no. of cigarettes smoked/d, whereas at 2 yrs GR is related to the smoking status, but not to the no. of cigarettes smoked; and (6) GR is not due to fetal hypoxia.

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