Harmfulness of maternal smoking has been demonstrated in many studies. In this study, MSc Isabell Rumrich shows that even smoking only during early pregnancy affects the development of the fetus. In a register-based epidemiological study of 1.4 million mother-child pairs in Finland in 1991-2016, smoking quit during the first trimester was associated with an increased risk to be born with low weight, short body length, and small brains size.
The analysis of body proportions at birth indicated a stronger reduction in body length and in brain size than in weight. The effects were slightly more pronounced for smoking throughout pregnancy than for smoking only during early pregnancy. The growth restriction stressed the importance of the period of early prenatal development, especially in brain development, and the limited potential to repair damages induced in early pregnancy.
In a chained risk model it was demonstrated that developmental exposures can explain part of currently unexplained disease burden. Smoking during pregnancy is associated with a higher prevalence of preterm birth, low birthweight and childhood overweight, which are known risk factors for chronic diseases in later life, in the exposed child. In a literature review, maternal smoking and the three risk factors have been found to be associated amongst others with cardiovascular disease, respiratory disease and mental illnesses in the child. This study estimated that about 34,000 healthy life years were lost due to maternal smoking and the three risk factors in the Finnish population in 2017. Estimating the contribution of maternal smoking to the development of the three risk factors, roughly 1,200 healthy years was attributable to smoking during pregnancy.
Between 1991 and 2015 roughly 213,000 children were exposed to maternal smoking during their fetal development. The number of children exposed to tobacco smoke throughout the whole pregnancy decreased from 10,000 in 1991 to 3,800 in 2016.
The doctoral dissertation of MSc Isabell Rumrich, entitled Maternal smoking, birth outcomes and later life health Estimation of the Developmental Origin of Disease Burden, will be examined at the faculty of Science and Forestry. The opponent in the public examination will be Professor Jouni Jaakkola, University of Oulu, and the custos will be Docent Otto Hänninen, Finnish Institute for Health and Welfare.
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