Timing of Maternal Smoking Cessation and Newborn Weight, Height, and Head Circumference

Association between maternal cigarette smoking cessation and risk of preterm birth in Western New York

BACKGROUND

Although many studies suggested the benefit of smoking cessation among pregnant women in reducing the risk of preterm birth (PTB), the timing of the effect of the cessation remains inconclusive.

OBJECTIVES

To examine the association of trimester-specific smoking cessation behaviours with PTB risk.

METHODS

We included 199,453 live births in Western New York between 2004 and 2018. Based on self-reported cigarette smoking during preconception and in each trimester, we created six mutually exclusive groups: non-smokers, quitters in each trimester, those who smoked throughout pregnancy, and inconsistent smokers. Risk ratios (RRs) and 95% confidence intervals (CIs) were estimated using Poisson regression to examine the association between smoking cessation and PTB. Effect modification by illegal drug use, maternal age, race and ethnicity and pre-pregnancy body mass index (BMI) was investigated multiplicatively by ratio of relative risk and additively by relative excess risk due to interaction (RERI).

RESULTS

Overall, 6.7% of women had a PTB; 14.1% smoked throughout pregnancy and 3.4%, 1.8% and 0.8% reported quitting smoking during the first, second and third trimesters, respectively. Compared to non-smokers, third-trimester cessation (RR 1.20, 95% CI 1.01, 1.43) and smoking throughout pregnancy (RR 1.27, 95% CI 1.21, 1.33) were associated with a higher PTB risk, while quitting smoking during the first or second trimester, or inconsistent smoking was not associated with PTB. A positive additive interaction was identified for maternal age and late smoking cessation or smoking throughout pregnancy on PTB risk (RERI 0.17, 95% CI 0.00, 0.36), and a negative interaction was observed for pre-pregnancy BMI ≥30 kg/m2 (ratio of relative risk 0.70, 95% CI 0.63, 0.78; RERI -0.42, 95% CI -0.56, -0.30).

CONCLUSION

Compared to non-smokers, smoking throughout pregnancy and third-trimester smoking cessation are associated with an increased risk of PTB, while quitting before the third trimester may not increase PTB risk.

Changes in anthropometry in full-term breastfed newborns and associated factors for the first month

OBJECTIVE

We aim to assess the changes and associated factors in newborn anthropometry in the first month for full-term, healthy, and exclusive-breastfed infants.

METHODS

Neonatal anthropometric measurements were taken on day 5, day 15, and day 30 after delivery. Generalized estimating equations (GEE) analyzed the changes.

RESULTS

From 169 mother-newborn pairs, GEE showed that weight gain during the first month was influenced by maternal body mass index (BMI), delivery type, birth weight, and jaundice after adjusting confounding factors (p < .05). The neonatal length was affected by the smoking status of parents, gestational maternal health problems, maternal height, birth weight, and jaundice (p < .05). Neonatal head circumference was influenced by the smoking status of parents, gestational maternal health problems, maternal BMI, delivery type, maternal height, and birth weight.

CONCLUSION

Adverse perinatal factors including mother's smoke exposure, maternal obesity and diabetes, cesarean birth, and neonatal hyperbilirubinemia influence anthropometry in the first months of life.

Association of Maternal Age and Blood Markers for Metabolic Disease in Newborns

Pregnancy at an advanced maternal age is considered a risk factor for adverse maternal, fetal, and neonatal outcomes. Here we investigated whether maternal age could be associated with differences in the blood levels of newborn screening (NBS) markers for inborn metabolic disorders on the Recommended Universal Screening Panel (RUSP). Population-level NBS data from screen-negative singleton infants were examined, which included blood metabolic markers and covariates such as age at blood collection, birth weight, gestational age, infant sex, parent-reported ethnicity, and maternal age at delivery. Marker levels were compared between maternal age groups (age range: 1544 years) using effect size analyses, which controlled for differences in group sizes and potential confounding from other covariates. We found that 13% of the markers had maternal age-related differences, including newborn metabolites with either increased (Tetradecanoylcarnitine [C14], Palmitoylcarnitine [C16], Stearoylcarnitine [C18], Oleoylcarnitine [C18:1], Malonylcarnitine [C3DC]) or decreased (3-Hydroxyisovalerylcarnitine [C5OH]) levels at an advanced maternal age (≥35 years, absolute Cohen's d > 0.2). The increased C3DC levels in this group correlated with a higher false-positive rate in newborn screening for malonic acidemia (p-value < 0.001), while no significant difference in screening performance was seen for the other markers. Maternal age is associated with inborn metabolic differences and should be considered together with other clinical variables in genetic disease screening.

Long-term adverse influence of smoking during pregnancy on height and body size of offspring at ten years old in the UK Biobank cohort

Background

To explore the long-term relationship between maternal smoking during pregnancy and early childhood growth in the UK Biobank cohort.

Methods

To estimate the effect of maternal smoking during pregnancy on offspring height and body size at ten years old, we performed binary logistic analyses and reported odds ratios (OR) as well as 95% confidence intervals (95%CIs). We also implemented the cross-contextual comparison study to examine whether such influence could be repeatedly observed among three different ethnicities in the UK Biobank cohort (n = 22,140 for White, n = 7094 for South Asian, and n = 5000 for Black). In particular, we conducted the sibling cohort study in White sibling cohort (n = 9953 for height and n = 7239 for body size) to control for unmeasured familial confounders.

Results

We discovered that children whose mothers smoked during pregnancy had greater risk of being shorter or plumper at age ten in the full UK Biobank White cohort, with 15.3% (95% CIs: 13.0%∼17.7%) higher risk for height and 32.4% (95%CIs: 29.5%∼35.4%) larger risk for body size. Similar associations were identified in the South Asian and Black ethnicities. These associations were robust and remained significant in the White sibling cohort (12.6% [95%CIs: 5.0%∼20.3%] for height and 36.1% [95%CIs: 26.3%∼45.9%] for body size) after controlling for family factors.

Conclusion

This study robustly confirms that maternal smoking during pregnancy can promote height deficit and obesity for offspring at ten years old. Our findings strongly encourage mothers to quit smoking during pregnancy for improving growth and development of offspring.

Cigarette Smoking Abstinence Among Pregnant Individuals Using E-Cigarettes or Nicotine Replacement Therapy

Importance

Smoking cigarettes during pregnancy can impair maternal and child health, and pregnant individuals have increasingly used electronic cigarettes (e-cigarettes) for various reasons, including quitting smoking.

Objective

To assess smoking abstinence rates among pregnant individuals who used e-cigarettes compared with those who used nicotine replacement therapy (NRT).

Design, Setting, and Participants

This cohort study is a secondary data analysis of phase 8 of the US Pregnancy Risk Assessment Monitoring System, conducted between 2016 and 2020. Eligible participants included pregnant individuals who smoked combustible cigarettes within the 3 months before pregnancy and either used e-cigarettes or NRT during pregnancy. Data analysis was conducted from March 2022 to April 2023.

Exposures

Combustible cigarette use within 3 months before pregnancy and use of either e-cigarettes or NRT during pregnancy.

Main Outcomes and Measures

The primary outcome was the individual's self-reported smoking abstinence status during the last 3 months of pregnancy. Weighted percentages were reported and weighted multivariable logistic regression models were used to examine the association of e-cigarette use vs NRT with smoking abstinence. A propensity score was used to control for confounding by sociodemographics, pregnancy characteristics, prepregnancy smoking intensity, depression, behavioral support, and hookah use.

Results

The cohort included 1329 pregnant individuals (759 ≥25 years [60.2%]; 766 non-Hispanic White individuals [79.8%]) of whom 781 had an education level of high school or lower (61.4%), and 952 had an annual household income of $48 000 or less (81.5%). Of the 1329 individuals, 890 (unweighted percentage, 67.0%) were existing e-cigarette users, 67 (unweighted percentage, 5.0%) were new e-cigarette users, and 372 (unweighted percentage, 28.0%) were NRT users. Compared with individuals who used NRT during pregnancy, individuals who used e-cigarettes had a higher rate of smoking abstinence in late pregnancy (456 individuals [50.8%] vs 67 individuals [19.4%]; propensity score adjusted odds ratio [OR], 2.47; 95% CI, 1.17-5.20; P = .02). In the secondary analysis stratified by the timing of e-cigarette use initiation, existing users of e-cigarettes who initiated before pregnancy had a higher smoking abstinence rate than NRT users (446 users [53.1%] vs 67 users [19.4%]; adjusted OR, 2.61; 95% CI, 1.23-5.51; P = .01). However, new e-cigarette users who initiated use during pregnancy had a similar smoking abstinence rate in late pregnancy when compared with NRT users (10 users [20.6%] vs 67 users [19.4%]; adjusted OR, 1.13; 95% CI, 0.22-5.87; P = .88).

Conclusions and Relevance

These findings suggest that individuals who used e-cigarettes during pregnancy had a higher smoking abstinence rate in late pregnancy than individuals who used NRT, especially for those who initiated e-cigarette use before pregnancy, indicating that replacement of cigarettes with e-cigarettes during pregnancy may be a viable strategy for harm reduction.