Counselling for smoking cessation during pregnancy reduces tobacco-specific nitrosamine (NNAL) concentrations: A randomized controlled trial

Effectiveness of smoking cessation interventions among pregnant women: An updated systematic review and meta-analysis

OBJECTIVE

To carry out a systematic review of systematic reviews with an update of the existing evidence relating to a broad range of smoking cessation interventions, including psycho-social, digital and pharmacologic interventions, for pregnant women.

DATA-SOURCES

Search was conducted in March 2022 in PubMed, EMBASE, and Cochrane in two stages: 1) a search of systematic reviews and meta-analyses, published from January 2012 through January 2022; 2) an update of those that fulfilled eligibility criteria reproducing the primary search strategy.

STUDY ELIGIBILITY CRITERIA

We selected randomized clinical trials (RCTs) that evaluated the effectiveness of pharmacological, digital, and psychosocial interventions in aged 18 years and over who were daily smokers, and compared these with routine care, less intense interventions or placebo.

STUDY APPRAISAL AND SYNTHESIS METHODS

Data from eligible studies were manually extracted by two authors and reviewed by a third. The quality of the reviews was evaluated using the AMSTAR scale, and risk of bias was measured with the Rob-2 tool and GRADE level of evidence.

RESULTS

The meta-analysis included 63 RCTs (n = 19849 women). The interventions found to be effective were: financial incentives (RR:1.77; 95%CI:1.21-2.58), counseling (RR:1.27; 95%CI:1.13-1.43) and long-term nicotine replacement therapy (NRT) (RR:1.53; 95%CI:1.16-2.01). Short-term NRT, bupropion, digital interventions, feedback, social support, and exercise showed no effectiveness. The GRADE level of evidence was moderate-to-high for all interventions, with the exception of long-term NRT.

CONCLUSIONS

Non-pharmacological interventions for smoking cessation are the most effective for pregnant women. The moderator analysis suggests that pregnant women of low socioeconomic status might benefit less from smoking cessation interventions than women of a high socioeconomic status. These women are usually heavier smokers that live in pro-smoking environments and could require more intensive and targeted interventions.

Effect of digital health, biomarker feedback and nurse or midwife-led counselling interventions to assist pregnant smokers quit: a systematic review and meta-analysis

OBJECTIVE

To assess the effect of digital health (DH), biomarker feedback (BF) and nurse or midwife-led counselling (NoMC) interventions on abstinence in pregnant smokers during pregnancy and postpartum.

SETTINGS

Any healthcare setting servicing pregnant women, including any country globally.

PARTICIPANTS

Pregnant women of any social, ethnic or geographical background who smoke.

METHODS

We searched Embase, Medline, Web Of Science, Google Scholar, PsychINFO, CINAHL and PubMed between 2007 and November 2021. We included published original intervention studies in English with comparators (usual care or placebo). Two independent assessors screened and abstracted data. We performed a random-effects meta-analysis, assessed risk of bias with the Cochrane Tool and used Grading of Recommendations Assessment, Development and Evaluation to assess the quality of evidence.

RESULTS

We identified 57 studies and included 54 in the meta-analysis. Sixteen studies assessed DH (n=3961), 6 BF (n=1643), 32 NoMC (n=60 251), 1 assessed NoMC with BF (n=1120) and 2 NoMC with DH interventions (n=2107). DH interventions had moderate certainty evidence to achieve continuous abstinence (CA) at late pregnancy (4 studies; 2049 women; RR=1.98, 95% CI 1.08 to 3.64, p=0.03) and low certainty evidence to achieve point prevalence abstinence (PPA) postpartum (5 studies; 2238 women; RR=1.46, 95% CI 1.05 to 2.02, p=0.02). NoMC interventions had moderate certainty evidence to achieve PPA in late pregnancy (15 studies; 16 234 women; RR=1.54, 95% CI 1.16 to 2.06, p<0.01) and low certainty evidence to achieve PPA postpartum (13 studies; 5466 women; RR=1.79, 95% CI 1.14 to 2.83, p=0.01). Both DH and BF interventions did not achieve PPA at late pregnancy, nor NoMC interventions achieve CA postpartum. The certainty was reduced due to risk of bias, heterogeneity, inconsistency and/or imprecision.

CONCLUSION

NoMC interventions can assist pregnant smokers achieve PPA and DH interventions achieve CA in late pregnancy. These interventions may achieve other outcomes.

Hair and nail nicotine levels of mothers and their infants as valid biomarkers of exposure to intrauterine tobacco smoke

INTRODUCTION

Tobacco use remains the single most modifiable cause of adverse pregnancy outcomes. It is crucial to be able to accurately quantify the burden of tobacco exposure on both the mother and fetus to have better measures of efficacy with interventions being studied.

METHODS

This is a descriptive and exploratory study conducted within a randomized controlled trial. Pregnant smoking and non-smoking women were followed from ≤22 weeks' gestation through delivery with monthly maternal smoking questionnaires, urine cotinine levels, and collection of maternal and infant hair and nail samples, at delivery. Nicotine was extracted and measured (ng/mg) using high-performance liquid chromatography with electrochemical detection.

RESULTS

Forty-six mother-infant dyads (34 pregnant smokers and 12 pregnant non-smokers) had successful completion of maternal and infant hair and nails samples. The median hair nicotine levels of the smoking mothers and their infants was significantly higher than those of the non-smokers (1.015 vs 0.037 ng/ mg, p<0.05 for the mothers; 0.445 vs 0.080 ng/mg, p<0.01 for the infants). Similarly, the median nail nicotine levels for smoking mothers and their infants were significantly higher than the non-smokers (2.130 vs 0.056 ng/mg, p<0.01 for the mothers; 0.594 vs 0.132 ng/mg, p<0.05 for the infants). We found a moderate but significant correlation between maternal hair and nail nicotine (r=0.64, p<0.001), infant hair and nail nicotine (r=0.64; p<0.001), maternal and infant hair nicotine (r=0.61, p<0.001), and maternal and infant nail nicotine levels (r=0.58, p<0.001).

CONCLUSIONS

Our study shows that both infant hair and nail nicotine levels are valid biomarkers of intrauterine tobacco smoke exposure, and can be used to identify prenatal smoke exposure, correlating well with the level of maternal nicotine exposure.