Development of Social and Demographic Differences in Maternal Smoking Between 1999 and 2014 in Norway

Grøtvedt, Liv; Kvalvik, Liv Grimstvedt; Grøholt, Else‐Karin; Akerkar, Rupali; Egeland, Grace M.

doi:10.1093/ntr/ntw313

Cited by 32 publications

(44 citation statements)

References 21 publications

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“…Still, we observed that smoking mothers used less folic acid supplements than non-smokers did ( Table 2). This may be related to an educational gradient in smoking habits (30) . Nearly half of women with pregestational diabetes were defined as supplement non-users.…”

Section: Discussionmentioning

confidence: 99%

Maternal use of folic acid and multivitamin supplements and infant risk of birth defects in Norway, 1999–2013

et al. 2020

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The association between folic acid supplementation and birth defects other than neural tube defects (NTD) remains unclear. We used a log-binomial regression model to investigate if periconceptional folic acid and/or multivitamin use was associated with birth defects in Norway with prospectively collected data from the Medical Birth Registry of Norway (MBRN) during 1999–2013. We used the European Surveillance of Congenital Anomalies (EUROCAT) classification system to define eleven organ-specific major birth defect groups (nervous system, eye, ear–face–neck, cardiovascular system, respiratory system, oral clefts, digestive system, abdominal wall, urinary system, genital organs and limb), with additional subgroups. Fetuses or infants whose mothers used folic acid and/or multivitamin supplements before and during pregnancy were classified as exposed. During the years 1999–2013, 888 294 (99·0 %) live-born infants, 6633 (0·7 %) stillborn infants and 2135 (0·2 %) fetuses from terminated pregnancies due to fetal anomalies were registered in the MBRN. Among the live- and stillborn infants of women who used vitamin supplements compared with infants of non-users, the adjusted relative risk (aRR) was 0·94 (95 % CI 0·91, 0·98) for total birth defects (n 18 382). Supplement use was associated with reduced risk of abdominal wall defects (aRR 0·58; 95 % CI 0·42, 0·80, n 377), genital organ defects (aRR 0·81; 95 % CI 0·72, 0·91, n 2299) and limb defects (aRR 0·81; 95 % CI 0·74, 0·90, n 3409). Protective associations were also suggested for NTD, respiratory system defects and digestive system defects although CI included the null value of 1. During the full study period, statistically significant associations between supplement use and defects in the eye, ear–face–neck, heart or oral clefts were not observed.

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Section: Discussionmentioning

confidence: 99%

Maternal use of folic acid and multivitamin supplements and infant risk of birth defects in Norway, 1999–2013

et al. 2020

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“…The proportion of pregnant smokers in Norway declined from 25% to 8% during the years 1999 to 2014 28 . Also mean placental weight and birthweight changed 29 .…”

Section: Methodsmentioning

confidence: 98%

Placental weight and birthweight: the relations with number of daily cigarettes and smoking cessation in pregnancy. A population study

Larsen

Haavaldsen

Bjelland

et al. 2018

International Journal of Epidemiology

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BackgroundWe studied associations of number of daily cigarettes in the first trimester with placental weight and birthweight in women who smoked throughout pregnancy, and in women who stopped smoking after the first trimester.MethodsWe included all women with delivery of a singleton in Norway (n = 698 891) during 1999–2014, by using data from the Medical Birth Registry of Norway. We assessed dose-response associations by applying linear regression with restricted cubic splines.ResultsIn total, 12.6% smoked daily in the first trimester, and 3.7% stopped daily smoking. In women who smoked throughout pregnancy, placental weight and birthweight decreased by number of cigarettes; however, above 11–12 cigarettes we estimated no further decrease (Pnon-linearity < 0.001). Maximum decrease in placental weight in smokers compared with non-smokers was 18.2 g [95% confidence interval (CI): 16.6 to 19.7], and for birthweight the maximum decrease was 261.9 g (95% CI: 256.1 to 267.7). In women who stopped smoking, placental weight was higher than in non-smokers and increased by number of cigarettes to a maximum of 16.2 g (95% CI: 9.9 to 22.6). Birthweight was similar in women who stopped smoking and non-smokers, and we found no change by number of cigarettes (Pnon-linearity < 0.001).ConclusionsIn women who smoked throughout pregnancy, placental weight and birthweight decreased non-linearly by number of cigarettes in the first trimester. In women who stopped smoking, placental weight was higher than in non-smokers and increased linearly by number of cigarettes; birthweight was almost similar to that of non-smokers.

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“…Age, parity and education have been indicated as possible determinants of smoking cessation in pregnancy (15,16). As the prevalence of snus use is rising while smoking is decreasing (12,13), we found the possibility to study also the tendency to quit tobacco in a time perspective important. Thus, we included the birth year of the newborn in the adjusted analyses.…”

Section: Methodsmentioning

confidence: 78%

Trends in maternal use of snus and smoking tobacco in pregnancy. A register study in Southern Norway

Rygh

Gallefoss

Grøtvedt³

2019

Preprint

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Background The use of tobacco products including Swedish snus (moist snuff) in pregnancy may cause adverse health outcomes. While smoking prevalence has decreased among fertile women in Norway, snus use has increased during the last years. We investigated whether these trends were reflected also during pregnancy in a population of women in Southern Norway. Methods Data on smoking tobacco and snus use at three time points before and during pregnancy for 20 844 women were retrieved from the electronic birth record for the years 2012-2017. The results for the three-year period 2015-2017 were compared with a previously studied period 2012-2014. Prevalence and quit rates of tobacco use within groups of age, parity and education were reported. Within the same groups adjusted quit rates were analyzed using logistic regression. Mean birthweight and Apgar score of offspring were calculated for tobacco-users and non-users. Results There was an increase of snus use before pregnancy from the period 2012-2014 to the period 2015-2017 from 5.1% (CI; 4.6 to 5.5) to 8.4% (CI; 7.8 to 8.9). Despite this, the use of snus during pregnancy did not increase from the first to the second period, but stabilized at 2.8% (CI; 2.5 to 3.2) in first trimester and 2.0% (CI; 1.7 to 2.2) in third trimester. Cigarette smoking decreased significantly both before and during pregnancy. Snus use and smoking during pregnancy were associated with a reduction in average birthweight, but no significant effects on Apgar scores. Odds ratios for quitting both snus and smoking tobacco during pregnancy were higher for women aged 25-34 years, for the primiparas and for those with a high level of education. Pregnant women were more likely to have quit tobacco use in the last time period compared to the first. Conclusions While smoking during pregnancy was decreasing, the use of snus remained constant, levelling off to around 3% in first trimester and 2% in third trimester. Approximately 25% of those that used snus, and 40% that smoked before pregnancy, continued use to the third trimester. This calls for a continuous watch on the use of snus and other nicotine products during pregnancy.

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Development of Social and Demographic Differences in Maternal Smoking Between 1999 and 2014 in Norway

Cited by 32 publications

References 21 publications

Maternal use of folic acid and multivitamin supplements and infant risk of birth defects in Norway, 1999–2013

Maternal use of folic acid and multivitamin supplements and infant risk of birth defects in Norway, 1999–2013

Placental weight and birthweight: the relations with number of daily cigarettes and smoking cessation in pregnancy. A population study

Trends in maternal use of snus and smoking tobacco in pregnancy. A register study in Southern Norway

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