Factors affecting use of nicotine replacement therapy and e-cigarettes in pregnancy

What was studied in this review? Nicotine replacement therapy (NRT) delivers nicotine without the harmful chemicals found in tobacco smoke. NRT helps some non-pregnant adults to stop smoking, but it does not seem to work so well in pregnancy. This may be because pregnant women generally do not use NRT as prescribed. Studies show that some pregnant women use e-cigarettes to help them cut down or quit, although their safety and effectiveness in pregnancy is not known. Little is known about the issues that influence pregnant women's use of NRT/e-cigarettes.

What is the aim of this review? To explore factors that affect whether women take up and use NRT or e-cigarettes to reduce or quit smoking in pregnancy.

What are the key messages of this review? Three main factors influence whether women take up and use NRT and e-cigarettes in pregnancy: advice women receive from health professionals on using NRT or e-cigarette in pregnancy, women's desire to protect their unborn baby from harm, and past personal experience with NRT. Each of these factors can either encourage or discourage women from using these products.

What are the key findings? We included 21 studies; 15 of these focused on NRT, 3 on e-cigarettes and 3 on both. Our findings suggest that women's desire to protect their unborn babies from harm is one of the main reasons they use these products. They also consider the advice from their health professionals; when professionals tell women that NRT or e-cigarettes are safer than smoking and that it is okay to use them in pregnancy, their confidence about using them increases. When women are told that NRT or e-cigarettes are as dangerous or more dangerous than smoking and that they should not use them when they are pregnant, they feel less confident about using them. Women's past experiences with NRT will also affect how willing they are to use NRT in pregnancy. For example, women who feel that NRT had worked for them (or someone they know) in the past were more confident about using it again. However, women who had negative experiences were more reluctant to use NRT. We conclude that consistent messages that are based on high-quality research and clearly explain how safe NRT and e-cigarettes are compared to smoking in pregnancy, could help women use NRT and e-cigarettes more consistently/as recommended. This may improve their attitudes towards NRT or e-cigarettes, increase their willingness to use these in their attempt to quit, and encourage them to stay smoke-free.

How up-to-date is this review? We searched for studies that had been published before 1 February 2019.

Authors' conclusions: 

Consistent messages from health professionals, based on high-quality evidence and clearly explaining the safety of NRT and e-cigarettes compared to smoking in pregnancy, could help women use NRT and e-cigarettes more consistently/as recommended. This may improve their attitudes towards NRT or e-cigarettes, increase their willingness to use these in their attempt to quit, and subsequently encourage them to stay smoke-free.

Read the full abstract...
Background: 

Nicotine replacement therapy (NRT) delivers nicotine without the toxic chemicals present in tobacco smoke. It is an effective smoking cessation aid in non-pregnant smokers, but there is less evidence of effectiveness in pregnancy. Systematic review evidence suggests that pregnant women do not adhere to NRT as prescribed, which might undermine effectiveness. Electronic cigarettes (e-cigarettes) have grown in popularity, but effectiveness and safety in pregnancy are not yet established. The determinants of uptake and use of NRT and e-cigarettes in pregnancy are unknown.

Objectives: 

To explore factors affecting uptake and use of NRT and e-cigarettes in pregnancy.

Search strategy: 

We searched MEDLINE(R), CINAHL and PsycINFO on 1 February 2019. We manually searched OpenGrey database and screened references of included studies and relevant reviews. We also conducted forward citation searches of included studies.

Selection criteria: 

We selected studies that used qualitative methods of data collection and analysis, included women who had smoked in pregnancy, and elicited participants' views about using NRT/e-cigarettes for smoking cessation or harm reduction (i.e. to smoke fewer cigarettes) during pregnancy.

Data collection and analysis: 

We identified determinants of uptake and use of NRT/e-cigarettes in pregnancy using a thematic synthesis approach. Two review authors assessed the quality of included studies with the Wallace tool. Two review authors used the CERQual approach to assess confidence in review findings. The contexts of studies from this review and the relevant Cochrane effectiveness review were not similar enough to fully integrate findings; however, we created a matrix to juxtapose findings from this review with the descriptions of behavioural support from trials in the effectiveness review.

Main results: 

We included 21 studies: 15 focused on NRT, 3 on e-cigarettes, and 3 on both. Studies took place in five high-income countries. Most studies contributed few relevant data; substantially fewer data were available on determinants of e-cigarettes. Many studies focused predominantly on issues relating to smoking cessation, and determinants of NRT/e-cigarette use was often presented as one of the themes.

We identified six descriptive themes and 18 findings within those themes; from these we developed three overarching analytical themes representing key determinants of uptake and adherence to NRT and/or e-cigarettes in pregnancy. The analytical themes show that women's desire to protect their unborn babies from harm is one of the main reasons they use these products. Furthermore, women consider advice from health professionals when deciding whether to use NRT or e-cigarettes; when health professionals tell women that NRT or e-cigarettes are safer than smoking and that it is okay for them to use these in pregnancy, women report feeling more confident about using them. Conversely, women who are told that NRT or e-cigarettes are as dangerous or more dangerous than smoking and that they should not use them during pregnancy feel less confident about using them. Women's past experiences with NRT can also affect their willingness to use NRT in pregnancy; women who feel that NRT had worked for them (or someone they know) in the past were more confident about using it again. However, women who had negative experiences were more reluctant to use NRT.

No trials on e-cigarette use in pregnancy were included in the Cochrane effectiveness review, so we considered only NRT findings when integrating results from this review and the effectiveness review. No qualitative studies were conducted alongside trials, making full integration of the findings challenging. Women enrolled in trials would have agreed to being allocated to NRT or control group and would have received standardised information on NRT at the start of the trial. Overall, the findings of this synthesis are less relevant to women's decisions about starting NRT in trials and more likely to help explain trial participants' adherence to NRT after starting it.

We considered most findings to be of moderate certainty; we assessed findings on NRT use as being of higher certainty than those on e-cigarette use. This was mainly due to the limited data from fewer studies (only in the UK and USA) that contributed to e-cigarette findings. Overall, we judged studies to be of acceptable quality with only minor methodological issues.

Share/Save