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- Rumrich, I, et al.
(författare)
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Effects of maternal smoking on body size and proportions at birth: a register-based cohort study of 1.4 million births
- 2020
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 10:2, s. e033465-
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Tidskriftsartikel (refereegranskat)abstract
- The aim of our work was to analyse the effect of maternal smoking on body size and body proportions of newborns when the mother had smoked only during the first trimester, in comparison with continued smoking after the first trimester. Furthermore, we have evaluated how growth restriction associated with maternal smoking contributes to changes in body proportions.DesignRegister-based cohort studySettingMaternal Exposure (MATEX) cohort identified from the Finnish Medical Birth Register.ParticipantsSingleton births without congenital anomalies and missing data (1.38 million) from 1 January 1991 to 31 December 2016.MethodsLogistic regression was used to quantify the effect of maternal smoking, stratified by the maternal smoking status.Outcome measuresBody proportions indicated by low brain-to-body ratio (defined as <10th percentile); high ponderal index and high head-to-length ratio (defined as >90th percentile); small body size for gestational age at birth (defined as weight, length or head circumference <10th percentile) and preterm birth (<37 weeks) and low birth weight (2500 g).ResultsContinued smoking after the first trimester was associated with high ponderal index (OR 1.26, 95% CI 1.23 to 1.28), low brain-to-body ratio (1.11, 1.07–1.15) and high head-to-length ratio (1.22, 1.19–1.26), corresponding with absolute risks of 22%, 10% and 19%, respectively). The effects were slightly lower when smoking had been quit during the first trimester. Similar effects were seen for the body size variables and low birth weight. Preterm birth was not associated with smoking only during first trimester.ConclusionsMaternal smoking, independent of smoking duration during pregnancy, was associated with abnormal body proportions resulting from larger reduction of length and head circumference in comparison to weight. The effects of having quit smoking during the first trimester and having continued smoking after the first trimester were similar, suggesting the importance of early pregnancy as a sensitive exposure window.
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- Rumrich, IK, et al.
(författare)
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Smoking during pregnancy in Finland - Trends in the MATEX cohort
- 2019
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Ingår i: Scandinavian journal of public health. - : SAGE Publications. - 1651-1905 .- 1403-4948. ; 47:8, s. 890-898
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Tidskriftsartikel (refereegranskat)abstract
- Aims: In Finland, smoking rates in the general population are decreasing due to increased awareness of the adverse effects and tightened tobacco legislation. However, previous studies have shown that smoking in pregnant Finnish women remained as high as in the general Finnish female population at around 15% in 2010. Our aim was to describe temporal and spatial trends in smoking behaviour, and determinants of changes in smoking behaviour between first and second pregnancy. Methods: Self-reported smoking from the Finnish Medical Birth Register covered the years 1991–2015 ( N=1,435,009). The association of maternal age and socioeconomic status with smoking rate was analysed. Spatial trends were assessed at municipality level. Results: The overall smoking rate during early pregnancy remained fairly stable at around 15% from 1991 to 2015, but increased in teenage and young women below 25 years of age. The mean smoking rate (36%) was higher in these age groups than in older pregnant women (11%). Through the study period the smoking rate remained higher in blue collar workers compared with higher socioeconomic groups. Between the first and second child, on average only 4% of women started to smoke and 41% quitted. Smoking rates developed less favourably in Eastern Finland. Conclusions: The observed increase in smoking rate during pregnancy in teenage and young women is concerning. Pregnancy is a trigger point for smoking cessation in a big fraction of pregnant women. More studies are needed to explain the opposite trends of smoking rates in Northern and Western Finland compared with Eastern Finland.
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