Maternal pregnancy smoking in three Brazilian cities: trends and differences according to education, income, and age

The effect of active and passive smoking during pregnancy on birth outcomes: A cohort study in Shanghai

INTRODUCTION

China is the largest tobacco consumer in the world, and tobacco poses a serious threat to the health of pregnant women. However, there are relatively few domestic studies on smoking during pregnancy and childbirth outcomes among pregnant women. The purpose of this study was to analyze the effect of active and passive smoking on pregnant women and their pregnancy outcomes, providing evidence and recommendations for intervention measures.

METHODS

This was a cohort study in Shanghai from April 2021 to September 2023. According to the smoking status of pregnant women, they were divided into three groups: active smokers, passive smokers and non-smokers. A self-designed questionnaire was utilized to conduct the survey, and their pregnancy outcomes were tracked and followed up.

RESULTS

A total of 3446 pregnant women were included in this study, among which 2.1% were active smokers, 43.5% were passive smokers, and 54.4% were non-smokers. The average age of the pregnant women was 29.9 years, and 41.2% had a university degree or higher. The education level of active smokers and passive smokers was significantly lower than that of non-smokers (p<0.05).The average gestational age of non-smokers was 38.6 weeks, and the birth weight was 3283.2 g, which was higher than those of active smokers and passive smokers (p<0.05). Logistic regression analysis showed that passive smoking increased the likelihood of preterm birth (AOR=1.38; 95% CI: 1.05-1.81), low birth weight (AOR=1.53; 95% CI: 1.10-2.12), and intrauterine growth restriction (AOR=1.35; 95% CI: 1.02-1.79), while active smoking increased the likelihood of preterm birth (AOR=2.98; 95% CI: 1.50-5.90), low birth weight (AOR=4.29; 95% CI: 2.07-8.88), intrauterine growth restriction (AOR=2.70; 95% CI: 1.37-5.33) , and birth defects (AOR=2.66; 95% CI: 1.00-6.97).

CONCLUSIONS

Our findings illustrate that active and passive smoking can lead to adverse pregnancy outcomes. This study provides data on the relationship between smoking during pregnancy and delivery outcomes among pregnant women. In the future, we need more effective strategies to protect pregnant women from the harm of tobacco.

Physical activity in birth cohorts of three Brazilian cities (Ribeirão Preto, Pelotas, and São Luís): A cross-sectional study

OBJECTIVE

To describe the prevalence of physical activity among subjects from birth cohorts of three cities located in different regions of Brazil according to sociodemographic characteristics and sex, comparing the relationships within and between cohorts.

METHODS

Cross-sectional study involving 12,724 adolescents and young adults who participated in five birth cohorts: Ribeirão Preto [1978/79 (37/39 years old in 2016) and 1994 (22 years in 2016)]; Pelotas [1982 (30 years in 2012) and 1993 (22 years in 2015)], and São Luís [1997/98 (18/19 years in 2016)]. Leisure-time physical activity was evaluated with questionnaires (insufficiently active: <150 min/week and active: ≥150 min/week) and moderate and vigorous physical activity (MVPA) was objectively measured by accelerometry. Those, in each city, were evaluated accordingly to skin color, socioeconomic classification, and study/work activities.

RESULTS

The prevalence of leisure-time physical activity ranged from 29.2% at 30 years old in Pelotas to 54.6% among adolescents from São Luís. The prevalence of leisure-time physical activity was higher among younger people (54.6% in São Luís 1997), while the same was not observed for total physical activity. MVPA (3rd tercile) was higher in the cohorts from Pelotas and São Luís. The prevalence of leisure-time physical activity and MVPA was higher in men. The data showed that the variation in physical activity was associated with sex and sociodemographic conditions in all cohorts.

CONCLUSION

Sociodemographic characteristics should be considered when promoting leisure-time physical activity and actions aimed at young people, and adults who are more socioeconomically vulnerable should be encouraged.

Factors associated with neonatal-near miss: birth cohorts in three Brazilian cities - Ribeirão Preto, Pelotas and São Luís, Brazil

The aim of this study was to investigate the association of sociodemographic factors, lifestyle, maternal reproductive profile and prenatal and childbirth care with neonatal near miss (NNM) morbidity in four birth cohorts. This study involved four population-based birth cohorts: Ribeirão Preto (RP) and São Luís (SL) (2010), Pelotas 2004 (PEL04) and 2015 (PEL15). NNM was defined when one or more of the following conditions were present: birthweight <1,500 g, 5-minute Apgar score <7, gestational age <32 weeks, and report of congenital malformations. The covariates were obtained with questionnaires applied to the puerperal women. Some particularities between cohorts were identified. In the RP and SL cohorts, factors of the more distal levels (sociodemographic, lifestyle, and reproductive profile) were associated with NNM. On the other hand, proximal factors related to healthcare were more significant for the occurrence of NNM in PEL. Only the absence of prenatal care was associated with NNM in all cohorts: RP (OR=4.27, 95%CI 2.16-8.45), SL (OR=2.32, 95%CI 1.09-4.94), PEL04 (OR=4.79, 95%CI 1.59-14.46), and PEL15 (OR=5.10, 95%CI 2.60-9.97).

Maternal smoking during pregnancy and intelligence quotient of offspring aged 18 and 30 years: Evidence from two birth cohorts in southern Brazil

Maternal smoking during pregnancy causes several harmful effects, including deficits in the intelligence quotient (IQ), a measure associated with academic achievements and higher socioeconomic position. We aimed to measure the association between maternal smoking during pregnancy and offspring's IQ in two birth cohorts from Pelotas, Brazil. Data from the 1982 and 1993 birth cohorts were analyzed. Smoking during pregnancy was ascertained at the perinatal follow-up, and IQ was measured at 30 years (1982) and 18 years (1993). Simple and multiple linear regressions were used for crude and adjusted analysis. Mediation analysis was performed using birth weight and breastfeeding as possible mediators. Data analysis was conducted in 2020. There were 3611 and 4050 participants from the 1982 and 1993 cohorts, respectively. After adjustment for potential confounders, the inverse association between smoking during pregnancy and children's IQ remained significant in both cohorts. Offspring of mothers who smoked during pregnancy had an average of 1.32 less IQ points (95%CI: -2.23, -0.242) in the 1982 cohort, and an average of 1.66 less IQ points (95%CI: -2.42, -0.90) in the 1993 cohort. Neither cohort showed association with paternal smoking (negative controls) after adjustment. Breastfeeding's mediated effects accounted for 26.2% and 23.9% of the association in the 1982 and 1993 cohorts, respectively, while birth weight's accounted for 6.8% and 30.1%, respectively; indirect effects were not significant. The inverse association between maternal smoking and IQ and the lack of association with paternal smoking reinforces our findings of a negative association between exposure and outcome.

Evolution of care during pregnancy and childbirth in the extreme south of Brazil

OBJECTIVES

To describe the evolution of care during pregnancy and childbirth among postpartum women living in the municipality of Rio Grande, Southern Brazil, using data from surveys carried out every three years between 2007 and 2019.

METHODS

Within 48 hours after delivery, a single, standardized questionnaire was applied to all mothers who had children in local hospitals and met the inclusion criteria. Demographic and reproductive characteristics, lifestyle habits, socioeconomic level of the family, and care received during pregnancy and childbirth were investigated. In the analysis, the chi-square test for linear trend was used to assess the distribution of indicators per survey.

RESULTS

A total of 12,645 parturients were interviewed (98% of the women eligible to participate in the surveys). In the period evaluated, the proportion of births fell 35% among adolescents and increased 25% among women aged 35 years and over. Mothers gained, on average, two years of schooling, and their families experienced an important economic improvement, followed by loss of income in the last survey. Maternal smoking, before and during pregnancy, fell by half. The rate of mothers who started prenatal care in the first trimester and the number of consultations and laboratory tests increased. Almost 60% of prenatal consultations and 80% of births took place in the Brazilian Unified Health System. In 2019, vaginal delivery was once again the most common. The rates of low birth weight (9%) and prematurity (17%) virtually remained unchanged.

CONCLUSIONS

We found an important change in the reproductive profile and increased coverage of various prenatal care and delivery services. Children continue to be born well, but low birth weight and prematurity remain endemic.

Individual and contextual variables associated with smoking and alcohol consumption during pregnancy

OBJECTIVE

to analyze the association between individual characteristics and housing context with smoking and alcohol consumption during pregnancy.

METHODS

a cross-sectional study with a probabilistic sample of 3,580 pregnant women who underwent prenatal care in the Unified Health System in 2019. The outcomes were firsthand, secondhand smoke and alcohol consumption during pregnancy. Individual characteristics and the living environment were used as exploratory variables.

RESULTS

living in a neighborhood with episodes of violence, without social cohesion and without urban elements that encourage physical activity was associated with smoking. Alcohol consumption during pregnancy was associated with living in environments that do not encourage physical activity. Smoking was also associated with lower income and education.

CONCLUSIONS

individual characteristics and the living environment are associated with smoking, secondhand smoke and alcohol consumption during pregnancy.