Smoking during pregnancy in Finland – Trends in the MATEX cohort

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.

Hospital admissions for lower respiratory tract infections after early‐, late‐, and post‐term birth

“…Young maternal age and low maternal socioeconomic status (SES) have been associated with an increased risk of hospital admission for bronchiolitis . Data on maternal SES were not available in the present study, but maternal smoking can be regarded as a surrogate marker of SES, because smoking during pregnancy correlates strongly with lower maternal SES in Finland …”

“…22 Data on maternal SES were not available in the present study, but maternal smoking can be regarded as a surrogate marker of SES, because smoking during pregnancy correlates strongly with lower maternal SES in Finland. 36 The association between births in other than level-III hospitals and the decreased risk of admission for LRTIs could be explained by the fact that level-III hospitals are located in larger cities with the highest population densities. Accordingly, a decreased risk of admission was seen in the Northern region, that is the region with the lowest population density.…”

Chained Risk Assessment for Life-Long Disease Burden of Early Exposures–Demonstration of Concept Using Prenatal Maternal Smoking

“…The MATEX cohort was used for exposure data [16]. In Finland in 2016, about 6.8% of newborns were exposed to smoking only during the fist trimester and additional 7.0% were exposed to maternal smoking also after the 1st trimester (Table 1).…”

“…Prenatal maternal smoking is a known early exposure associated with adverse birth outcomes [14,15]. Despite public health efforts, maternal smoking remains to be prevalent with 14% of all newborns exposed in Finland in 2015 [16]. Exposure to maternal smoking leads to epigenetic changes in the exposed fetus [16][17][18][19], indicating persistent changes in susceptibility to environmental exposures [5].…”

“…Despite public health efforts, maternal smoking remains to be prevalent with 14% of all newborns exposed in Finland in 2015 [16]. Exposure to maternal smoking leads to epigenetic changes in the exposed fetus [16][17][18][19], indicating persistent changes in susceptibility to environmental exposures [5]. Emerging evidence is suggesting DNA methylation as a mechanism for the effect of maternal smoking on birth weight [20].…”