Abstract
Maternal smoking during pregnancy and fetal growth retardation might adversely affect early lung development and increase the risks of asthma-related symptoms.
The study of the associations of maternal smoking during pregnancy and fetal growth, measured in different periods of pregnancy with asthma-related symptoms in early childhood.
Methods: We performed a 4 years (2006-2010) prospective population-based cohort study starting in pregnancy. Fetal growth retardation was defined as a decrease of 1 gestational age adjusted standard deviation score in weight from 3rd trimester to birth. Maternal smoking during pregnancy (I, II, III trimesters) and wheezing, lower respiratory tract infections (LRTI) and diagnosed asthma until the age of 3 years were assessed by questionnaires. Adjusted logistic regression analyses were performed in 1217 subjects.
Results: Maternal first trimester only smoking was not associated with asthma-related symptoms in the children. Continued maternal smoking during pregnancy was associated with wheezing at 1, 2 and 3 years with adjusted odds ratios (aOR) 1.47 (94% confidence interval 1.14 to 19.4), 1.51 (1.13, 2.10) and 1.60 (1.09, 2.37), and with LRTI at 2 years (aOR 1.69 (1.19, 2.41)) but not with diagnosed asthma. Fetal growth retardation was not associated with any asthma-related symptoms. Children of continued smoking mothers with fetal growth retardation had higher risks of wheezing than children of smoking mothers without fetal growth retardation.
Conclusions: Continued maternal smoking during pregnancy is associated with increased risks of wheezing in early childhood. These associations are stronger in children with fetal growth retardation.
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