Article Text

Effect of implementation strategies on the routine provision of antenatal care addressing smoking in pregnancy: study protocol for a non-randomised stepped-wedge cluster controlled trial
  1. Justine B Daly1,2,3,
  2. Emma Doherty1,2,3,
  3. Belinda Tully1,4,5,
  4. John Wiggers1,2,3,
  5. Jenna Hollis1,2,3,
  6. Milly Licata1,
  7. Michelle Foster6,
  8. Flora Tzelepis1,2,3,
  9. Christophe Lecathelinais1,
  10. Melanie Kingsland1,2,3
  1. 1Hunter New England Population Health, Hunter New England Local Health District, Wallsend, New South Wales, Australia
  2. 2School of Medicine and Public Health, College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales, Australia
  3. 3Population Health Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
  4. 4Armajun Aboriginal Health Service, Inverell, New South Wales, Australia
  5. 5Gomeroi Nation, New South Wales, Australia
  6. 6Nursing and Midwifery Services, Hunter New England Local Health District, New Lambton, New South Wales, Australia
  1. Correspondence to Dr Justine B Daly; Justine.daly{at}


Introduction Globally, guideline-recommended antenatal care for smoking cessation is not routinely delivered by antenatal care providers. Implementation strategies have been shown to improve the delivery of clinical practices across a variety of clinical services but there is an absence of evidence in applying such strategies to support improvements to antenatal care for smoking cessation in pregnancy. This study aims to determine the effectiveness and cost effectiveness of implementation strategies in increasing the routine provision of recommended antenatal care for smoking cessation in public maternity services.

Methods and analysis A non-randomised stepped-wedge cluster-controlled trial will be conducted in maternity services across three health sectors in New South Wales, Australia. Implementation strategies including guidelines and procedures, reminders and prompts, leadership support, champions, training and monitoring and feedback will be delivered sequentially to each sector over 4 months. Primary outcome measures will be the proportion of: (1) pregnant women who report receiving a carbon monoxide breath test; (2) smokers or recent quitters who report receiving quit/relapse advice; and (3) smokers who report offer of help to quit smoking (Quitline referral or nicotine replacement therapy). Outcomes will be measured via cross-sectional telephone surveys with a random sample of women who attend antenatal appointments each week. Economic analyses will be undertaken to assess the cost effectiveness of the implementation intervention. Process measures including acceptability, adoption, fidelity and reach will be reported.

Ethics and dissemination Ethics approval was obtained through the Hunter New England Human Research Ethics Committee (16/11/16/4.07; 16/10/19/5.15) and the Aboriginal Health and Medical Research Council (1236/16). Trial findings will be disseminated to health policy-makers and health services to inform best practice processes for effective guideline implementation. Findings will also be disseminated at scientific conferences and in peer-reviewed journals.

Trial registration number Australian New Zealand Clinical Trials Registry—ACTRN12622001010785.

  • Health policy
  • Health Education

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  • The stepped-wedge cluster design is appropriate for conducting a trial across multiple maternity services and demonstrates the feasibility of the intervention in an operational environment.

  • Implementation strategies have been developed using key implementation science frameworks and informed through surveys with maternity service staff.

  • Delivery of the 4-month intervention in the three sectors will occur sequentially in a non-randomised, pragmatic order.

  • A research coproduction approach has been employed in the design of the study and will be employed in its conduct and dissemination and all study processes and outputs will be reviewed for cultural appropriateness.


Smoking during pregnancy is associated with a wide range of pregnancy complications and adverse outcomes for the woman and her baby.1 There is a 71% increase in risk of infant mortality due to smoking, and impacts extend to childhood and adulthood.2 Women who smoke during pregnancy face a twofold to threefold increased risk of miscarriage, ectopic pregnancy, placenta previa, placental abruption and preterm labour.1 3 Babies of mothers who smoke during pregnancy are at an increased risk of stillbirth, perinatal death, low birth weight, preterm birth, sudden infant death syndrome, decreased lung function and respiratory infection.1 3 4

Globally, it is estimated that 1.7% of women smoke during pregnancy, with rates varying widely by country, ranging from 0.2% in Tanzania to 38.4% in Ireland.5 In Australia in 2021, 8.7% of pregnant women reported smoking at any time during pregnancy; however, smoking rates differ across geographical locations and socioeconomic and cultural groups.6 Smoking during pregnancy is more prevalent among women living remotely (36%), women in the most disadvantaged areas (18%) and among Aboriginal and Torres Strait Islander women (43%).6 These higher smoking rates exist within a complex historical context of colonisation, that is; tobacco being introduced as payment for work, racism, socioeconomic disadvantage, marginalisation and resulting circumstances.7 8

Quitting smoking prior to conception or during early pregnancy significantly reduces the risk of complications and adverse outcomes; however, quitting at any time during pregnancy can result in reductions in risk and provide health benefits for both the woman and baby.9 A 2017 Cochrane systematic review of 88 randomised controlled trials (RCT) including 28 403 women found that interventions which include behavioural smoking cessation support, including counselling and feedback, delivered by antenatal care providers can significantly increase smoking cessation rates in pregnancy and can reduce the number of babies born with low birth weight by 17%.10 Further, a 2020 systematic review of 11 RCTs involving 2412 women reported that pharmacological interventions in pregnancy using nicotine replacement therapy (NRT) may increase smoking cessation rates by up to 40%.11 Given that approximately two-thirds of women who quit smoking for pregnancy will relapse,12 it is also recommended that women who have recently quit are identified early in pregnancy and provided with support to remain abstinent during pregnancy and into the postpartum period.13 A 2014 systematic review of 2 RCTs and one controlled trial (n=1293) delivered by antenatal and postnatal care providers found that identification of recent quitters and provision of brief behavioural counselling increased the odds of maternal smoking abstinence (RR, 1.53; 95% CI 1.10 to 2.14; p=0.01).14

Consistent with systematic review evidence, Australian and international guidelines13 15–20 recommend that antenatal care providers deliver evidence-based smoking cessation support as part of routine antenatal care. Based on a condensed version of the 5As Framework,17 the following steps are recommended: (1) Ask—women about their smoking status (including whether they have quit in the past 12 months) using validated multiple-response questions to improve the accuracy of disclosure.21 Offer all pregnant women carbon monoxide (CO) breath screening to improve identification of smokers,22 23 and provide feedback to enhance engagement in behaviour change16; (2) Advise—for women identified as current smokers or recent quitters (last 12 months), provide brief counselling regarding the benefits of quitting (or remaining a non-smoker) and treatment options available to assist them to quit or prevent relapse; and (3) Help—provide brief behavioural counselling, facilitate access to NRT (when behavioural counselling alone is insufficient), and arrange follow-up cessation support, including referrals for telephone or face-to-face counselling services.16 18 20 In Australia, public maternity services are the largest provider of antenatal care, providing care for 55% of all birthing women across diverse population groups, including those with a high prevalence of risk and those who are disadvantaged.6 The implementation of such guidelines is particularly important in such services where women who report smoking or who have recently quit are over-represented.6

Despite the existence of evidence-based guidelines, the delivery of recommended smoking cessation support by antenatal care providers is less than optimal.24–26 A recent systematic review24 of 54 studies from 10 countries, involving 29 225 participants, reported that less than 60% of pregnant women who smoked were provided with brief counselling, only one-third were offered a referral for follow-up cessation counselling and only one-quarter were provided with NRT.24 Research conducted in Australian public maternity services suggests a similar pattern. Only 25% of women attending public maternity hospitals in Victoria were found to be referred for stop-smoking support and fewer than 50% followed up regarding their smoking at subsequent appointments.25 Similarly, only 30% of midwives from New South Wales (NSW) reported providing advice and behavioural support to women to quit, less than half always referred women to the Quitline or other cessation support services and less than 20% arranged follow-up.27 Surveys of antenatal care providers have also found that few smokers and recent quitters are followed up at subsequent antenatal visits, suggesting that relapse prevention remains a low priority.28

Multiple barriers impede the routine provision of guideline-recommended smoking cessation care during pregnancy in maternity services, including lack of knowledge regarding best practice,28 29 lack of confidence and skills,27 28 limited time and resources,28 30 unsupportive clinical environments and systems,28 29 perceptions that care will be ineffective30 and concerns regarding impact on relationships with pregnant women.26 28–31 Implementation strategies are methods or techniques used to address such barriers and enhance the adoption, implementation and sustainability of evidence-based practices.32 Strategies include clinician training,33–35 systems, policies and guidelines that support and prompt care delivery,36 clinical leadership,37 service champions38 and audit and feedback.35 39 40 Systematic review evidence from 714 studies involving 22 512 clinicians has shown that the use of multiple implementation strategies improves the delivery of desired clinical practices by up to 60%.41 The use of theoretical implementation science frameworks and tools42 43 to tailor implementation strategies to local contexts and barriers has been found to further enhance the success of implementation strategies.44 45

Two systematic reviews have examined the effectiveness of implementation strategies in improving the routine provision of guideline-recommended smoking cessation care by a range of antenatal care providers.31 46 A 2019 review of 6 controlled and 10 non-controlled studies, conducted in primary care and hospital-based clinics, targeting a range of antenatal care providers found that implementation strategies significantly increased the provision of smoking cessation care to pregnant women, including: asking (Cohen’s d: 0.47; 95% CI 0.13 to 0.81), advising (Cohen’s d: 0.46; 95% CI 0.02 to 0.90) and assisting with quitting (Cohen’s d: 0.65; 95% CI 0.46 to 0.83).31 The review found that intervention effectiveness was improved through tailoring and theory-based strategy selection, the inclusion of audit and feedback, and by use of at least three implementation strategies. Meta-analyses in the second systematic review of four RCTs conducted in primary care and hospital-based services by Doherty et al46 found that implementation strategies compared with usual practice increased asking (OR: 2.52; 95% CI 1.13 to 5.59), advising (OR: 4.32; 95% CI 3.06 to 6.11) and assisting to quit (OR: 6.34; 95% CI 1.51 to 26.63). No significant effect was found for arranging follow-up support (OR: 3.55; 95% CI 0.50 to 25.34). The most commonly employed strategies in these studies were educational meetings and educational materials. Other included strategies which have been found to be effective in improving care in other clinical settings, such as audit and feedback and use of local opinion leaders were not included in any of the studies. Of the eight included RCTs, two did not include all elements of guideline-recommended care and four did not include the use of behaviour change theories or frameworks to inform strategy selection.46 No economic evaluations of implementation strategies to improve evidence-based antenatal smoking cessation care have been reported. There is a need to investigate the effectiveness, and cost effectiveness, of theoretically informed implementation strategies addressing barriers to care on improving all elements of guideline-recommended smoking cessation care provision by antenatal care providers in public maternity services.


The aim of this study is to determine the effectiveness and cost effectiveness of implementation strategies in increasing the routine provision of recommended antenatal care for smoking cessation in public maternity services.


We hypothesise that implementation strategies will increase the receipt of CO breath screening for all women at first antenatal appointment by 7.2%, increase advice for quitting smoking/preventing relapse for current/ex-smokers by 17.6% and increase referral for smoking support/NRT for current smokers by 21.8%.


This study protocol is reported in accordance with The Standard Protocol Items: Recommendations for Interventional Trials Checklist (online supplemental file 1).

Study design and setting

A non-randomised stepped-wedge cluster-controlled trial will be conducted in all maternity services from three geographically defined sectors in a regional Health District in NSW, Australia. The maternity services provide care to approximately 7000 women annually in urban and rural areas.6

As shown in figure 1, continuous measurement of outcomes will occur via cross-sectional surveys with randomly selected pregnant women from 16 months prior to the delivery of the intervention (baseline period) in the first sector to 7 months postintervention completion in the third sector. Delivery of the 4-month intervention in the three sectors will occur sequentially. The order of intervention implementation in each sector will not be randomised, but pragmatic, to enable responsiveness to the context, functions and demands of an operational service delivery environment.

Figure 1

Data collection and intervention timeline for the stepped-wedge trial design.

A stepped-wedge cluster study design is recommended for the evaluation of complex practice change interventions in health services as it provides a number of pragmatic and scientific advantages over a cluster RCT design. It provides the same level of evidence as a cluster RCT47 but addresses the practical difficulty of recruiting enough equivalent services as is required for a parallel cluster RCT and increases study efficiency by using each group as its own control.48 49 The design also provides an opportunity for all participating services to receive the intervention, motivating clinician engagement and demonstrates the feasibility of the intervention in an operational environment, a key determinant of research translation.47

Participant eligibility and recruitment

Maternity services and antenatal care providers

All antenatal care providers who are the main providers of routine antenatal care within the participating maternity services will receive the implementation strategies, including registered midwives (clinical midwife educators (CMEs), clinical midwife specialists, clinical midwife consultants and community liaison midwives), medical practitioners (staff specialists in obstetrics, fellows, registrars, resident medical officers and general practice obstetricians), Aboriginal Health Practitioners, Aboriginal Health Workers and students. All antenatal care providers who work in participating maternity services at any time during the 4 months when the intervention is implemented in their sector will be invited to participate in a postintervention survey.

Pregnant women

It is intended that all pregnant women who attend participating services from the start of the intervention in their sector will receive the model of smoking cessation care. During the 35-month data collection period, women who have had an antenatal appointment at any of three time points: (1) the first public antenatal service appointment; (2) 27–28 weeks gestation; or (3) 35–36 weeks gestation will be eligible to participate in data collection surveys. These three time points were selected to provide an indication of care delivery across the schedule of antenatal care. Eligibility for survey participation will require women to be aged 18 years or older; more than 12 weeks and less than 37 weeks gestation; have a sufficient level of English language proficiency to complete the survey unaided; and be mentally and physically capable of completing the survey. Women will be ineligible to participate in data collection surveys if they are determined by a maternity service clinician to be inappropriate to contact for the survey (eg, due to medical or social issues); and/or are seeing a private provider as the primary provider of their antenatal care; and/or have given birth or had a negative pregnancy outcome; and/or had already been selected to participate in the survey in the past 4 weeks; and/or had previously declined participation in the survey. Characteristics of women deemed ineligible will be recorded and reported.

Each week, a sample of eligible women who have had an antenatal appointment in the past week (first visit, 27–28 weeks gestation or 35–36 weeks gestation) will be randomly selected via a computerised random-number generator by members of the research team not involved in delivering antenatal care. Selected women will be mailed a participant information statement explaining the purpose of the survey 1 week prior to receiving a phone call inviting them to participate in the survey. Verbal consent will be sought from the women to complete the telephone interview at the time of telephone contact. Those women declining the telephone survey will be offered the option of completing the survey online, in which case written consent will be sought. Based on cultural advice, women identified via the medical record data as being of Aboriginal or Torres Strait Islander origin and/or who are enrolled in an Aboriginal Maternal and Infant Health Service (AMIHS) will be first contacted by text message and invited to participate via telephone or online. Women will have the opportunity to decline participation at any point. Each day prior to survey contact, medical record data will be checked and any potential participants who have given birth or had a negative pregnancy outcome will be deemed ineligible and not contacted.

Participant blinding

Given the practice-change nature of the intervention, antenatal care providers in maternity services will be aware when their service is in the intervention period. Study personnel involved in collecting outcome data will be blind to the order of the delivery of the intervention across the sectors. Participants providing outcome data will be blind to the stage of intervention occurring in the service they attended.


Best practice care pathway for addressing smoking during antenatal care

A best practice care pathway for addressing smoking in pregnancy will be implemented in maternity services across the three participating sectors. The care pathway is consistent with international,16 Australian national13 15 20 and state18 antenatal clinical practice guidelines and is based on models of assessment and brief intervention that have been shown to increase smoking cessation and prevent relapse in pregnancy.10 11 50 The smoking cessation care pathway will consist of three key care elements: Ask, Advise and Help (see figure 2).

Figure 2

Smoking cessation care pathway. NRT, nicotine replacement therapy.

Ask—assessment of smoking status

At the first antenatal visit, all pregnant women will be offered CO screening using a CO Breath Monitor. At each subsequent antenatal visit, women identified as smokers or recent quitters (in the past 12 months) will be offered a CO breath test. Following the CO screening, all women will be asked about their smoking status (including whether they have quit in the past 12 months) using validated multiple-response questions to improve disclosure.21

Advise—provision of advice regarding smoking cessation

For women identified as smokers, antenatal care providers will discuss the benefits of quitting smoking for both baby and mother and the treatment options available to support cessation. For women who have recently quit smoking (in the last 12 months), antenatal care providers will discuss the benefits of remaining smoke free for both baby and mother, identify any withdrawal symptoms and discuss treatment options to support ongoing cessation.

Help—support and follow-up

All women identified as smokers will be offered a referral to the Quitline telephone counselling service. The Quitline is a free, government-funded service that provides access to professional telephone counsellors who provide up to six calls offering encouragement, resources and support to help smokers quit.51 For women who identify as Aboriginal and/or Torres Strait Islander, referral will be offered to the Aboriginal Quitline and to smoking cessation services within Aboriginal Community Controlled Health Services. If deemed clinically appropriate, women who smoke will be offered up to 12 weeks supply of free NRT. NRT approved by the Australian Therapeutic Goods Administration will be provided in line with current clinical guidance for pregnancy (first-line therapy intermittent formulation—4 mg gum or 15 mg inhalator, second-line therapy 21 mg patch).18 E-cigarettes are not currently recommended for use in pregnancy in Australia.18 19 For current smokers, smoking will be revisited at every antenatal visit by the antenatal care provider. All women who are identified as recent quitters will be assessed at every visit throughout their pregnancy for risk of relapse and provided appropriate support if required, including NRT, behavioural support and referral to the Quitline.

Women who smoke and use e-cigarettes (vape) will be included in this smoking care pathway and provided support to quit smoking using approved NRT.18 19 However, women who solely vape will not be included in the smoking care pathway.

Implementation strategies

The following evidence-based organisational and individual clinician-focused strategies will be used to support implementation of the smoking cessation care pathway as part of routine antenatal care. The specific content of each strategy and the prioritisation of resources allocated to the strategies will be tailored to the context of each individual sector. The strategies will be delivered to antenatal care providers in each sector over a 4-month period. Such an approach has been used in previous successful implementation trials conducted by the research team.52

  1. Leadership37: existing clinical networks and maternity service clinical leaders will be engaged to provide authorisation and endorsement of the initiative through staff meetings, attendance at training and monitoring and communication of performance feedback. A clinical expert group will provide clinical guidance to support implementation. Aboriginal staff and partner organisations will provide oversight of the cultural appropriateness of the implementation.

  2. Prompts and reminders53: physical point of care prompts and clinic room resources will be provided to prompt recommended care delivery.

  3. Local guidelines and procedures36: local guidelines and procedures will be developed to outline the model of care elements, including local referral procedures for each maternity service site and midwife-initiated medicine procedures to facilitate the direct provision of NRT.

  4. Service champion38 54: a CME will be employed in each of the three health sectors for the 4-month intervention phase to facilitate the delivery of the implementation strategies. They will train and advise staff, monitor performance and provide feedback to antenatal clinicians and service managers.

  5. Clinician training and resources34: multimode (online and face-to-face) training will be provided to clinicians, facilitated by the CMEs. Staff will participate in 1–1.5 hours of training. Face-to-face training sessions will be rostered into routine educational sessions. The training will address local barriers to care delivery and use evidence-based training elements including roleplays and case studies.34 Printed educational resources will be provided. CO breath monitors will be provided for each clinic room.

  6. Care delivery monitoring and feedback (including academic detailing)35: data from patient surveys and electronic medical records will be used to compile monthly reports on compliance with the delivery of the care pathway. Performance measures will be built into existing monitoring and accountability frameworks.

Tailoring content and prioritisation of implementation strategies to each site’s context

The following steps were undertaken at sites within each of the three sectors to prioritise implementation strategies and tailor content to each site’s contextual factors:

  1. Antenatal care providers were invited to complete surveys to determine priority barriers to their implementation of the smoking cessation care pathway. The two least implemented elements of the care pathway, as identified via formative work and existing literature,55 were included in the survey (Assessment of recent quitters and referral to Quitline). The surveys used the best–worst scaling method56 57 to elicit the priority barriers.

  2. The priority barriers were defined in terms of the Theoretical Domains Framework45 55 and Capacity, Opportunity, Motivation—Behaviour model42 and mapped using the Behaviour Change Wheel42 to intervention functions and The Theory and Techniques Tool58 to behaviour change techniques (see online supplemental table 1).

  3. Consultation with Aboriginal community members, Aboriginal Community Controlled Health Services within the participating sectors, AMIHS staff and Aboriginal staff within the study team was undertaken to embed cultural perspective into the content of implementation strategies.

  4. Final refinement of implementation strategies and development of strategy content was undertaken following consultation with key antenatal care providers and managers from each of the three participating sectors. All modifications made to the smoking cessation care pathway and implementation strategies due to site context and needs will be reported according to the Framework for Reporting Adaptations and Modifications to Evidence-based Implementation Strategies (FRAME-IS).59

Intervention delivery timeline

The implementation strategies will be implemented in each sector sequentially for 4 months (figure 1). Given their organisational and system focus, all strategies, other than the service champion, have the potential to continue to be implemented following this 4-month period, subject to the operational decisions of the services.

Control and contamination

Usual care

Prior to delivery of the implementation strategies in each of the three sectors, usual antenatal care for smoking during pregnancy will be provided.

Potential for contamination

As the research team will control the initiation and delivery of the implementation strategies, the strategies will not be accessible to antenatal care providers during the baseline (control) phase. Although potential for contamination during this phase from staff movement between sectors is possible, it is likely to be limited due to the structural and organisational nature of the strategies. Information on any significant movement of antenatal care providers between participating sectors will be recorded.

Patient and public involvement

A research coproduction approach has been used to develop and design the study.52 The smoking care pathway was developed in partnership with key stakeholders from maternity services and informed by feedback from pregnant women. Small focus groups were conducted across the sectors with Aboriginal mothers to understand the acceptability and local context of smoking cessation, privileging the voice of Aboriginal women. These groups informed the development of culturally responsive smoking cessation and referral pathways and cultural inclusion for Aboriginal and Torres Strait Islander peoples. A Cultural Review Group containing only Aboriginal members will review all project resources and dissemination outputs.


Primary outcomes

  1. The proportion of women attending a first antenatal appointment that report receiving a CO breath test using a CO monitor.

  2. The proportion of women who were smoking or had recently quit smoking at their first antenatal appointment that report receiving quit/relapse advice and discussion of the risks of smoking and benefits of quitting/staying a non-smoker (at the first visit, 28-week visit or 36-week visit).

  3. The proportion of women who were smoking at their first antenatal appointment that report offer of help to quit smoking by referral to the Quitline Service or culturally appropriate referral services (for Aboriginal women) or offer of NRT (at the first visit, 28-week visit or 36-week visit).

Secondary outcome

The proportion of women who were smoking or had recently quit at their first antenatal appointment that report receiving a CO breath test at a follow-up appointment (28 weeks or 36 weeks).

Cost effectiveness

The incremental costs and outcomes of the implementation strategies will be presented as a cost-effectiveness analysis. The analysis will adhere to cost and economic analysis guidelines.60

Process measures

  • Participant-reported acceptability of each of the elements of the smoking care pathway will be assessed through questions in the women’s telephone/online survey at each time point.

  • Antenatal care providers will be asked to report perceived usefulness of and exposure to implementation strategies; current barriers and facilitators to delivery of care and perceived sustainment of the best practice care pathway.61

Data collection procedures

Data collection for outcome measures

Data for all primary outcomes will be collected through cross sectional telephone/online surveys with women who have recently attended a first, 28-week or 36-week antenatal appointment. The telephone and online survey scripts are identical. Both surveys have been reviewed for cultural appropriateness and pilot tested with women in the target group to test comprehension, logic flow and survey length. These data collection procedures have been previously successfully used by the research team.52

Data collection for process measures

Data for process measures will be collected via surveys with women (described above) and antenatal care providers. Online surveys of antenatal care providers will be conducted 1–2 months postintervention completion in each sector. All eligible antenatal care providers at the participating sites will be invited to complete the survey on tablet computers in regular in-services and clinic meetings. Additional process data on exposure to implementation strategies including training participation will be collected using project management logs completed by project staff.

Data collection for economic analyses

Data regarding resources expended on materials (point of care prompts), equipment (CO breath monitors) labour (CME wages) and other expenses incurred in developing and executing the implementation strategies will be recorded prospectively in project management logs. Such costs will include actual labour costs for training, managerial oversight and all activities undertaken by the CMEs using salary awards. Costs will be reported in Australian Dollars. Research costs including data collection and analysis will be excluded.

Data management and monitoring

Management of trial data will be in accordance with a data management protocol and Aboriginal data management protocol that has been developed and approved by the project’s advisory group and Aboriginal Review Group. Data from the telephone surveys will be directly entered into RedCap and data quality processes such as range checks for data values will be built into the program. Data will then be extracted into SAS (V.9.3 or later) for analysis. Data will be stored securely, password protected and only accessible to the research team as per the requirements of the Hunter New England Human Research Ethics Committee (HNEHREC) and the Aboriginal Health and Medical Research Council.

The following processes will be put in place to review and monitor each of the study elements to ensure consistency with study and data protocols: a Computer Assisted Telephone Interview Management Team will meet fortnightly to monitor participant recruitment and undertake quality control reviews, local leadership groups from each sector will monitor implementation of strategies at individual maternity sites and the completion of staff surveys. Clinical aspects of care delivery will be monitored through existing independent quality assurance processes such as the Quality Use of Medicines Committee. Trial conduct will be independently assessed by the Hunter New England Local Health District Research Governance Office and HNEHREC. Regular progress reports and approvals for any amendments to the study protocol will be submitted to the HNEHREC.

Sample size and power calculations

Based on previous trials conducted by the research team in maternity services, it is expected that 60% of invited women, or 15 women (5 per sector), will consent to participate in surveys each week for each of the 3 visit types (‘first antenatal visit’, ‘28’ or ‘36’ weeks) giving a total of 45 women each week. This will yield 6560 data points, across the 3 sectors, during a data collection period of 35 months (figure 1), sufficient to detect (ICC 0.01, 80% power, Bonferroni adjusted alpha 0.0167): (1) 7.2% absolute increase in receipt of CO monitor screening at first antenatal appointment (baseline: 2%); (2) 17.6% absolute increase for advice for quitting smoking/preventing relapse (baseline: 48%); and (3) 21.8% absolute increase for arranging referral for smoking support/NRT for current smokers (baseline: 40%). These predicted increases are consistent with prior smoking cessation trials in pregnancy.31 46

Statistical analysis

Preintervention and postintervention primary outcome data will be analysed using mixed effects logistic regression models to detect change in reported receipt of the recommended elements of smoking cessation care for all three sectors combined. Separate models will be fitted for each outcome.

The main predictor of interest will be a before/after intervention indicator variable as well as a fixed effect for time, and a random intercept for intervention period. The intervention will be declared effective if the coefficient for the intervention period variable is below the threshold of 0.0167 for any of the individual outcomes. For any outcomes that are significant, additional time-series analyses will be performed over the postintervention periods to determine if slope changes occur, as an indicator of sustainability. SAS (V.9.3 or later) will be used for all statistical analyses.

Research trial governance

Trial governance will be provided by an advisory group consisting of researchers, policy-makers, practitioners and clinical experts with expertise related to smoking cessation, health promotion, implementation science, health economics, study design and statistics, Aboriginal health, obstetrics and midwifery. A project team consisting of research staff and practitioners will develop and operationalise implementation strategies and data collection components of the trial according to the study protocol. Implementation leadership groups established within each of the three participating sectors will provide advice on aspects of the smoking cessation care pathway and implementation strategies that require site-specific tailoring and oversee delivery at their sites. Aboriginal peoples will be included at all stages of project governance, including the advisory group, project team and sector implementation leadership groups.

Trial status

Baseline data collection for the preimplementation phase commenced in March 2021. Data collection for the postimplementation phase will be completed in March 2024.

Ethics and dissemination

Ethics approval was obtained through the HNEHREC (16/11/16/4.07; 16/10/19/5.15) and the Aboriginal Health and Medical Research Council (1236/16). There are no predetermined criteria for trial discontinuation as it is not anticipated that any events would occur that would warrant discontinuing the trial. Any unforeseen adverse events will be reported to the HNEHREC (primary approval committee). The trial is registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12622001010785; registered 19 July 2022). Any protocol modifications will be updated in the registry and any deviations from original protocol will be reported in study outcome papers. Participation in surveys for both the women and staff will be voluntary. All potential participants will receive information about the study prior to providing verbal informed consent for telephone surveys or written consent for those completed online or via pen and paper. Trial findings will be disseminated to key stakeholder groups including clinical representatives, Aboriginal partners and community organisations. Findings will also be shared with health policy-makers and health services to inform the best practice processes for effective guideline implementation. Trial outcomes will be disseminated through scientific conferences and in peer-reviewed publications. In accordance with the Aboriginal Data Management Protocol and the principles of Indigenous Data Sovereignty, no access to data sets will be made available without the explicit approval of the Aboriginal Review Group.

Protocol version

Protocol version 1, 2 November 2023.

Ethics statements

Patient consent for publication


Supplementary materials

  • Supplementary Data

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  • X @Em_Doherty

  • Contributors JBD, MK and JW led the overall development of the research protocol. JBD led the development of the manuscript. JBD, MK, JW, ED, ML, JH and FT contributed to the development of the rationale and background for the protocol. JBD, BT, ML, MK, ED and JH contributed to the development of the smoking cessation care pathways and implementation support strategies. BT facilitated the provision of cultural advice and the establishment of cultural governance structures. MF contributed clinical expertise relevant to the midwifery and obstetrics workforce and maternity services setting. JBD and MK contributed to the development of the data collection methods generally. CL provided overall guidance for the study design and data analysis. All authors read and approved the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.