Clinical and biochemical effects of environmental tobacco smoking on pregnancy outcome

Environmental tobacco smoke exposure during pregnancy affects complications and birth outcomes in women with and without asthma

Background

It is known that environmental tobacco smoke (ETS) has adverse effects on pregnancy and birth outcomes. We aimed to assess the impact of ETS in pregnant women with and without asthma.

Methods

A cohort study was conducted from August 2014 to June 2015 enrolling 1603 pregnant women during their 2nd trimester. Data on tobacco exposure were collected at first visit and women were followed through pregnancy till postpartum.

Results

Of the 1603 women, 231 reported passive smoking, 223 non-asthmatics and 8 asthmatics. Women exposed to ETS during pregnancy were more likely to have an infant admitted to the pediatric ward (10.8% vs. 6.5%, p = 0.026) and to have low one- and five-minute Apgar scores (1 min: 6.1% vs. 2.6%, p = 0.011; 5 min: 2.2% vs. 0.7%, p = 0.039). Complications of pregnancy were also elevated in women exposed to ETS (53.7% vs. 42.3%, p = 0.002). Asthma had no additional effect beyond the impact of ETS except for cesarean sections that were more frequent in women with asthma exposed to ETS.

Conclusions

Due to the small number of women with asthma exposed to ETS, combined effects of asthma and ETS were only found for cesarean sections. Still counseling of pregnant women about adverse effects of ETS should consider women’s asthma as an additional reason to avoid ETS.

Environmental & occupational exposure & female reproductive dysfunction

All individuals are exposed to certain chemical, physical, biological, environmental as well as occupational factors. The data pertaining to role of these factors on female reproduction are scanty as compared to male. The available data suggest the adverse effects of certain toxicants, viz., metals such as lead, cadmium and mercury, pesticides such as bis(4-chlorophenyl)-1,1,1-trichloroethane and organic solvent such as benzene, toluene and ionizing radiation on the female reproductive system affecting directly the organ system or impacting in directly through hormonal impairments, molecular alterations, oxidative stress and DNA methylation impairing fertility as well as pregnancy and its outcomes. Thus, there is a need for awareness and prevention programme about the adverse effects of these factors and deterioration of female reproductive health, pregnancy outcome and offspring development as some of these chemicals might affect the developing foetus at very low doses by endocrine disruptive mechanism.

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

BACKGROUND

Environmental tobacco smoke (ETS) exposure during pregnancy can cause preterm delivery and childhood cancer. The aim of this study was to measure ETS exposure in pregnant women and in newborn infants in Israel using urinary cotinine measurements, to assess predictors of ETS exposure in these vulnerable groups, and to assess associations with birth effects (birth weight, birth length, head circumference) in newborn infants.

METHODS

We analyzed urinary cotinine and creatinine in 265 non-smoking pregnant women and 97 newborns, and analyzed associations with self-reported exposure to ETS, paternal smoking, sociodemographic variables and with birth outcomes (birth weight, birth length, head circumference).

RESULTS

37.7% of pregnant women and 29.0% of infants had urinary cotinine concentrations above the level of quantification (LOQ) of 1 μg/L, whereas 63.8% and 50.5%, respectively, had urinary cotinine concentrations above the level of detection (LOD) of 0.5 μg/L. Median unadjusted and creatinine adjusted urinary concentrations of cotinine in pregnant women were 0.7 μg/L, and 0.9 μg/g creatinine, respectively, and in newborn infants were 0.5 μg/L, and 1.3 μg/g creatinine, respectively. We did not find an association between maternal and infant urinary cotinine level. Maternal (but not infant) urinary cotinine was significantly associated with paternal smoking (p < 0.05). Infant (but not maternal) cotinine above the LOQ was negatively associated with birth weight (p < 0.05).

CONCLUSIONS

In this high socioeconomic cohort, almost a third of newborn infants born to non-smoking mothers had quantifiable levels of urinary cotinine. This is the first study showing that newborns with quantifiable urinary cotinine levels have lower birth weight.

Secondhand Smoke Exposure During Pregnancy and Mothers' Subsequent Breastfeeding Outcomes: A Systematic Review and Meta-Analysis

Secondhand smoke exposure of non-smoking women during pregnancy is associated with a higher risk of adverse birth outcomes. However, the available evidence regarding the association between expectant mothers’ secondhand smoke exposure and breastfeeding outcomes remains limited. This systematic review aimed to examine associations between secondhand smoke exposure of nonsmoking women during pregnancy with the initiation, prevalence, and duration or breastfeeding compared to women who were breastfeeding and had not been exposed to secondhand smoke. Women who smoked during pregnancy were excluded. We included case-control, cross-sectional, and cohort studies with a comparison control group. Medline CINAHL, and EMBASE were searched in January 2017. After screening 2777 records we included eight prospective cohort studies. The risk of bias assessment tool for non-randomized studies indicated a high risk of outcome assessment blinding. Meta-analysis of two studies established that the odds of discontinuation of any brestfeeding before six months were significantly increased in the secondhand smoke exposed women (pooled odds = 1.07 [95%CI = 1.01, 1.14], two studies, 1382 women). Therefore, secondhand smoke might be associated with discontinuing any breastfeeding before six months. More research is necessary to understand the association between secondhand smoke and the initiation, prevalence and duration of breastfeeding.