Newborn infant urinary cotinine and birth outcomes in the Jerusalem Environment Mother and Child Cohort Study

Barriers and Enablers to Implementing a Smoke-free Home and Car During Pregnancy: A Qualitative Study Among Expectant Israeli Fathers

INTRODUCTION

Secondhand smoke exposure during pregnancy is a significant cause of negative health effects. This study aims to identify barriers and facilitators for implementing a smoke-free home and car among expectant Israeli fathers.

AIMS AND METHODS

Twenty-four qualitative semistructured telephone interviews were audio-recorded, transcribed, and analyzed according to a reflexive and collaborative thematic approach. Inclusion criteria were being male, Hebrew speaker, age ≥18 years, smoking at least one cigarette a day, and living with their nonsmoking pregnant spouse. The Capability, Opportunity and Motivation for Behavior (COM-B) model was used as a theoretical model for analysis.

RESULTS

Participants reported feeling a strong responsibility for their pregnant spouse's comfort and health, stating that they are doing the best they can to reduce their spouse's secondhand smoke exposure (Motivation). Participants had a low level of knowledge about specific secondhand smoke health consequences, effective strategies to reduce secondhand smoke exposure, with incorrect perceptions about what constitutes exposure (Capability). Couple relationships were not affected by the husband's smoking habits, and participants expressed mutual consideration and understanding (Opportunity). Participants also expressed positive attitudes regarding smoke-free home and car implementation but emphasized that any changes have to be their own decision (Motivation).

CONCLUSIONS

The present study identified principal Capability, Opportunity and Motivation barriers and facilitators that influence Israeli expectant fathers' decision to implement a smoke-free home and car. Those findings will inform the development of a digital behavioral intervention targeting expectant fathers to reduce prenatal secondhand smoke exposure.

IMPLICATIONS

Secondhand smoke exposure during pregnancy is a significant cause of negative health effects. Interventions among expectant fathers that focus on creating a smoke-free home and car may be effective because pregnancy has been identified as a "window of opportunity" that generates a strong motivation and creates a sense of urgency to change smoking behavior, while being considered more achievable than smoking cessation. Interventions might be effective if they focus on strengthening the parental responsibility among expectant fathers and emphasize the benefits of a smoke-free home and car, while maintaining male autonomy and increasing skills to effectively implement a smoke-free home and car.

Evaluating association of smoking status during pregnancy with adverse birth outcomes using urinary cotinine concentration: The Japan environment and Children's study (JECS)

Urinary cotinine concentration (UCC) reflects smoking status. However, in pregnant women, its association with adverse birth outcomes related to fetal growth is not widely known. Thus, we aimed to explore this relationship by focusing on dose-response relationships. We investigated 86,638 pregnant women enrolled between 2011 and 2014 in a prospective cohort study in Japan and observed three birth outcomes (preterm birth, low birth weight, and small-for-gestational age). We measured UCC in the second or third trimester, and categorized the participants using cut-off values (negative cotinine concentration, passive cotinine concentration, and active cotinine concentration corresponding to non-smokers, passive smokers, and active smokers, respectively). Logistic regression analyses were conducted to evaluate the risks, and dose-response relationships were visualized using restricted cubic spline curves. Analyses based on self-reported smoking status were also performed. We found that in low active and highly active cotinine concentrations, the adjusted odds ratios (aORs) of birth outcomes were significantly increased (preterm birth, 1.24 [95% CI 1.06-1.46], 1.39 [95% CI 1.19-1.62]; low birth weight, 1.40 [95% CI 1.24-1.58], 2.27 [95% CI 2.05-2.53]; small-for-gestational age, 1.35 [95% CI 1.19-1.52], 2.39 [95% CI 2.16-2.65]). Restricted cubic spline curves demonstrated risk elevations in the active cotinine concentration range. Our research revealed dose-response relationships between UCC during pregnancy and the risks of preterm birth, low birth weight, and small-for-gestational age. Measurement of UCC to ascertain smoking status during pregnancy may be a useful approach for predicting the risks of these birth outcomes.

Dose-response relationships between maternal urinary cotinine and placental weight and ratio of placental weight to birth weight: The Japan Environment and Children's Study

INTRODUCTION

Studies on the relationship between maternal self-reported smoking status and placental weight report inconsistent results. This study examined the relationships between maternal urinary cotinine concentration and placental weight and the ratio of placental weight to birth weight (PW/BW ratio). The study also examined the relationship between maternal smoking status, as determined by cotinine concentration, with placental weight and with PW/BW ratio, stratified by sex of offspring.

METHODS

Our analysis used information of 91,049 mother-child pairs enrolled in the Japan Environment and Children's Study. Maternal urinary cotinine concentration was quantified (during the second or third trimester) with high-performance liquid chromatography-tandem mass spectrometry. Using restricted cubic splines, placental weight and PW/BW ratio were plotted against natural log-transformed cotinine concentration. Taking cotinine levels of <0.17 ng/mL, 0.17 to <21.5 ng/mL (natural log-transformed values, -1.77 to 3.07), and ≥21.5 ng/mL as indicative of non-smokers, passive smokers, and active smokers, respectively, the relationships between maternal smoking status and placental weight and PW/BW ratio were examined, adjusting for confounders.

RESULTS

Placental weight and PW/BW ratio increased with increasing cotinine concentration. After cotinine reached a certain concentration, the placental weight decreased in male offspring whereas it plateaued in female offspring. Compared with not smoking, active smoking during pregnancy significantly increased placental weight and PW/BW ratio.

CONCLUSION

Placental weight responded as an inverted U-shape whereas the PW/BW ratio followed a J-shape with increasing maternal urinary cotinine concentration measured during pregnancy, suggesting exposure to tobacco smoke induces a disproportionate reduction in fetal growth. The effect of tobacco smoke on placental growth varied by sex of offspring.

Active and Passive Maternal Smoking During Pregnancy and Birth Outcomes: A Study From a Developing Country

Background:

Smoking is one of the modifiable risk factors for adverse maternal and neonatal outcomes and is associated with low birth weight, preterm birth, respiratory, antepartum and intrapartum stillbirth, and perinatal death as well as long-term morbidity in offspring and sudden unexpected infant death. The rate of smoking in low- and middle-income countries is still relevantly high, and Jordan is no exception.

Objective:

To investigate the effect of active and passive smoking during pregnancy on adverse pregnancy outcomes.

Methods:

The case-control study was conducted in Jordan in June 2020. Healthy women with full-term singleton pregnancy (n = 180) were interviewed and stratified into three groups: Group I, active smokers; Group II, passive smokers; and Group III, nonsmokers. The study variables included demographic data, current pregnancy history, cotinine level of mothers and newborns, and perinatal outcomes. Statistical analysis was performed using the application package IBM SPSS 25. Various algorithms of statistical analysis were used depending on the type of distribution of feature and data quality. The threshold for statistical significance was set at p < 0.05.

Results:

Active smokers had significantly lower gestational age at delivery compared to passive and nonsmoking women (p = 0.038 and p = 0.003, respectively). Neonates from active smoking mothers had significantly lower birth weight compared to neonates from passive and nonsmoking women (p = 0.016 and p = 0.019, respectively), significantly lower head and chest circumferences compared to babies from passive smokers (p < 0.001 and p = 0.036, respectively), and significantly lower first-minute Apgar score compared to those from nonsmoking women (p = 0.023). The urine cotinine level was significantly higher in both active and passive smoking women (both p < 0.01), and it was significantly higher in newborns who had been exposed to smoking in utero despite maternal active or passive smoking status (both p < 0.001). There was a weak negative correlation between urine cotinine level and birth weight: r = –0.14 for maternal cotinine level and r = –0.15 for neonate cotinine level.

Conclusions:

The current study illustrated that smoking during pregnancy leads to offspring with reduced birth weight, birth length, and head and chest circumference; reduces delivery gestational age; and lowers the first-minute Apgar score. Our study findings highlight the need for further research issued to smoking effects on perinatal outcomes, the implementation of actions to develop cessation interventions in the preconception period, and an evaluation of useful interventions to enhance a smoking-free environment during pregnancy.