Nearly Half of Women Who Stop Smoking During Pregnancy Go Back to Smoking Soon After Baby Is Born

BMJ Open. 2017; 7(eleven): e018746.

Smoking and quit attempts during pregnancy and postpartum: a longitudinal UK cohort

,¹ Sophie Orton,^one Jo Leonardi-Bee,^two Emma Brotherton,^one Laura Vanderbloemen,³ Katharine Bowker,¹ Felix Naughton,⁴ Michael Ussher,⁵ Kate E Pickett,^six Stephen Sutton,⁷ and Tim Coleman¹

Sue Cooper

¹ Sectionalization of Primary Care, University of Nottingham, University Park, Nottingham, Uk,

Sophie Orton

¹ Division of Primary Care, Academy of Nottingham, Academy Park, Nottingham, UK,

Jo Leonardi-Bee

² Partition of Epidemiology and Public Health, Academy of Nottingham, Nottingham, UK,

Emma Brotherton

^one Division of Primary Care, University of Nottingham, University Park, Nottingham, UK,

Laura Vanderbloemen

³ Department of Primary Care and Public Health, Imperial College London, London, United kingdom of great britain and northern ireland,

Katharine Bowker

¹ Sectionalisation of Primary Care, University of Nottingham, University Park, Nottingham, United kingdom of great britain and northern ireland,

Felix Naughton

⁴ School of Health Sciences, University of E Anglia, Norwich, Norfolk, UK,

Michael Ussher

^v Population Wellness Research Institute, St George'southward University of London, London, United kingdom of great britain and northern ireland,

Kate East Pickett

⁶ Department of Health Sciences, Academy of York, York, Uk,

Stephen Sutton

⁷ Behavioural Science Group, University of Cambridge, Cambridge, United kingdom of great britain and northern ireland,

Tim Coleman

¹ Partition of Master Intendance, University of Nottingham, University Park, Nottingham, UK,

Received 2017 Jul xviii; Revised 2017 Sep viii; Accustomed 2017 Sep 28.

Supplementary Materials

Reviewer comments

GUID: 35F08B21-1925-4062-8CCE-52F4D70CD56D

Author'south manuscript

GUID: 5D95A197-BD0E-47BB-B9C2-60341E4A72E5

Abstract

Objectives

Pregnancy motivates women to try stopping smoking, but little is known about timing of their quit attempts and how quitting intentions change during pregnancy and postpartum. Using longitudinal data, this study aimed to document women'south smoking and quitting behaviour throughout pregnancy and after delivery.

Pattern

Longitudinal cohort survey with questionnaires at baseline (8–26 weeks' gestation), late pregnancy (34–36 weeks) and 3 months later delivery.

Setting

Two motherhood hospitals in 1 National Health Service infirmary trust, Nottingham, England.

Participants

850 meaning women, anile xvi years or over, who were current smokers or had smoked in the 3 months before pregnancy, were recruited betwixt August 2011 and August 2012.

Effect measures

Self-reported smoking behaviour, quit attempts and quitting intentions.

Results

Smoking rates, adjusting for non-response at follow-up, were 57.4% (95% CI 54.one to threescore.7) at baseline, 59.one% (95% CI 54.9 to 63.4) in late pregnancy and 67.1% (95% CI 62.7 to 71.5) three months postpartum. At baseline, 272 of 488 current smokers had tried to quit since becoming pregnant (55.7%, 95% CI 51.3 to 60.1); 51.3% (95% CI 44.7 to 58.0) tried quitting between baseline and late pregnancy and 27.four% (95% CI 21.7 to 33.2) after childbirth. The percentage who intended to quit inside the next month roughshod as pregnancy progressed, from xl.four% (95% CI 36.1 to 44.eight) at baseline to 29.7% (95% CI 23.8 to 35.6) in late pregnancy and fourteen.2% (95% CI 10.0 to eighteen.3) postpartum. Postpartum relapse was lower among women who quit in the 3 months earlier pregnancy (17.8%, 95% CI 6.1 to 29.4) than those who stopped between baseline and late pregnancy (42.9%, 95% CI 24.6 to 61.iii).

Conclusions

Many meaning smokers make quit attempts throughout pregnancy and postpartum, only intention to quit decreases over time; there is no show that smoking rates fall during gestation.

Keywords: smoking abeyance, pregnancy, longitudinal enquiry, quit attempts, postpartum relapse, survey research

Strengths and limitations of this study

• As far as nosotros are enlightened, this is the only study to investigate timing of quit attempts and propensity to stop smoking during pregnancy and postpartum and to quantify longitudinal changes.

• Smoking behaviour is self-reported rather than validated; misreporting due to retrieve bias may have been minimised by collecting data at three time points and by there existence no expectation that they should try to cease smoking.

• Afterwards survey findings were adapted using multiple imputation to help accost not-response bias due to attrition.

• As the written report was conducted in but i geographical area of the UK and participants were predominantly white British, findings might non be generalisable; nevertheless, the demographic contour of participants was like to that of other Great britain cohorts of significant smokers.

Introduction

Smoking in pregnancy is associated with increased risks of miscarriage, stillbirth, prematurity, low birth weight, perinatal morbidity and mortality, neonatal and sudden infant decease, baby respiratory problems, poorer infant cognition and adverse infant behavioural outcomes.^{1 2} Internationally, large numbers of pregnant women smoke, with rates between 12% and 22% in high-income countries^3–6 and rates increasing in emerging and developing economies.⁷ Pregnancy is probably the effect which most motivates female smokers to try quitting; for instance, in the Uk, over l% of significant smokers effort to stop⁵ and significant women are, therefore, particularly probable to be interested in receiving abeyance support. Some wellness systems systematically offer such support; in the UK, this is largely done in early pregnancy,^eight although official guidance recommends that support is provided throughout gestation.⁹

We are not aware of any studies that have investigated when, in pregnancy, smokers take the greatest propensity to endeavor stopping, the timing of whatever quit attempts and potential influences on this. Exterior of pregnancy and postpartum, most adults tend to have fairly stable smoking behaviour.¹⁰ Although overall smoking rates in pregnancy have declined, a significant proportion of women continue to smoke throughout pregnancy.¹¹ However, many women who smoke before pregnancy accept varied smoking behaviour after conception,^{5 11–sixteen} and although it is logical to try to minimise fetal exposure to tobacco fume by offering abeyance support in early pregnancy, support may be welcomed at other times in gestation. In add-on, of those that do terminate, many relapse within the first few months postpartum.^{17 xviii} Relatively few studies of prenatal smoking behaviour have been longitudinal,^{12 13 15 16 19–23} with merely two of these following upwards women postpartum,^{12 13} and the only two studies to have been conducted in the UK are now over twenty years onetime.^{12 nineteen} Chiefly, none of these studies asked nigh number of quit attempts or reported when in pregnancy women accept tried to quit. To help focus smoking cessation interventions at the virtually constructive leverage points, we demand contemporary, longitudinal data on the smoking and quitting behaviours of significant women. Consequently, we investigate the frequency and timing of pregnant smokers' quit attempts and the factors associated with these. We too endeavor to quantify individual-level changes in smoking behaviour during these times.

Methods

Study design and configuration

A longitudinal cohort report was undertaken; eligible women were aged sixteen years or over, 8–26 weeks pregnant and currently smoking or had smoked regularly during the three months immediately prior to finding out they were pregnant. Surveys were conducted at recruitment (eight–26 weeks' gestation), in tardily pregnancy (34–36 weeks' gestation) and 3 months later commitment. Total methods and characteristics of the recruited participants, including factors associated with being a electric current smoker, are detailed elsewhere.²⁴ STROBE guidance was used for reporting.²⁵ Ethical approval was given by Derbyshire Research Ethics Proportionate Review Sub-Commission.

Study setting and regimen

Women were recruited between August 2011 and August 2012 when attending routine hospital or ultrasound appointments at two antenatal clinics within Nottingham University Hospitals National Health Service Trust (City Hospital and Queen'due south Medical Centre). Women attending clinics first completed a screening questionnaire and those eligible and willing completed a baseline questionnaire and were sent follow-up questionnaires by mail or via an email spider web link.

Measurements

At baseline, 'recent ex-smokers' were women who reported non smoking currently but had washed so during the 3 months before finding out they were pregnant. On later questionnaires, women who reported quitting smoking since the previous survey were also defined as 'contempo ex-smokers'. At any time, if women reported smoking either every day or occasionally (smoke, only not every twenty-four hours), they were classified equally smokers and were asked further details about this, including if they had made any quit attempts and how many of these attempts had lasted at least 24 hours. On all questionnaires, women were asked about timescales of time to come intentions to quit (within next 2 weeks/next xxx days/next 3 months/not planning to quit) (since finding out they were significant/since completing the first questionnaire/since the birth of their baby) and most urges to fume (6-point Likert scale ranging from 'no urges' to 'extremely strong'). The Heaviness of Smoking Index (HSI) was calculated as the sum of scores from two items of the Fagerström Test of Cigarette Dependence²⁶ (scores range from 0 to 6; higher score indicates greater cigarette dependence). The questionnaires are bachelor as online supplementary appendix to this article.

Statistical assay

To quantify the proportion of quit attempts made after the first trimester of pregnancy, we aimed to recruit 850 participants.²⁴ Analyses were conducted using Stata 5.fourteen.0 (StataCorp).

Descriptive statistics summarised participants' characteristics and smoking behaviour at each fourth dimension indicate; we compared those responding to all three questionnaires with those who did not past using Χ^two and t tests for categorical and continuous variables, respectively, with P values of <0.05 deemed significant. Characteristics found to be significantly associated with not-completion of afterwards questionnaires, and hence with absenteeism of smoking data were used with multiple imputation to suit for compunction of smoking behaviour at later time points.

An exploratory analysis was performed to investigate the factors associated with reporting having made a quit attempt of any duration on the baseline questionnaire. For this analysis, items were dichotomised; six self-efficacy items that had high internal consistency (Cronbach's α=0.95)²⁷ were combined into a unmarried score out of thirty with women scoring ≥25 considered to have high self-efficacy. Univariable logistic regression assay was used to calculate an OR with 95% CIs for each variable (age,^{28 29} ethnicity,³⁰ qualifications held,²⁸ previous pregnancy,^{28 29 31 32} number of cigarettes smoked per twenty-four hour period, HSI,^{29 31 33} partner smoking status,²⁹ occupation,³⁴ planned or surprise pregnancy,^{28 35–37} depression, long-term disability or mental disease,³⁸ smoking behavior and self-efficacy³⁹). Variables which showed a significant clan (P<0.05) in the univariable analysis were included in a multivariable logistic regression model. Variables that accomplished significance (P<0.05) remained in the multivariable model and all not-pregnant variables identified from the univariable analysis were re-entered into the model consecutively to assess whether they became pregnant. The final multivariable model included only significant variables (P<0.05). A likelihood ratio test identified that age should be included in the multivariable assay as a continuous variable. Where collinearity between variables was anticipated (eg, the number of cigarettes smoked per day and HSI), we included the variable that resulted in a improve plumbing equipment model. As this analysis only included baseline data, we did not need to take business relationship of attrition.

Multiple imputation for missing outcome information for smoking in late pregnancy (34–36 weeks' gestation) and at 3 months after delivery was performed using Stata'southward mi command, based on 20 iterations. The outcomes were imputed using multivariable logistic regression models based on the following baseline variables: historic period, smoking condition, gestation, general health, depression, previous pregnancy, smoking in previous pregnancy, smoking urges, qualifications and ethnicity. All baseline variables were included in the analysis in a dichotomised format. The percentage of women smoking at each outcome was obtained using Rubin's rule.^xl Where necessary, an augmented regression arroyo was used to overcome issues relating to perfect prediction during the multiple imputation.

Results

Figure 1 summarises questionnaire response rates. Of 1101 eligible women, 966 (88%) completed the baseline survey, and 850 (77%) consented to receive the after surveys. Questionnaires were returned past 509 (59.9%) in late pregnancy and by 476 (56.0%) at 3 months postpartum with 407 (47.8%) women completing all three.

Diagram showing recruitment and flow of participants through the written report.

Participants had similar sociodemographic characteristics to those in previous pregnancy cohorts and have been reported elsewhere.²⁴ Just over half (488, 57.4%) were current smokers and 729 (85.7%) of the 850 women in the cohort reported their longer-term quitting intentions (data missing for 121 (fourteen.two%)). Of these 729 women, 424 (58.2%) planned to terminate smoking permanently, 21 (2.9%) intended to stop until their babe was born and 181 (24.8%) were unsure; notwithstanding, 103 (14.i%) did not plan to stop. Amid the 272 smokers who reported a quit attempt at baseline, 14 (7.6%) reported stopping for >30 days, 32 (12.2%) for seven–30 days, 126 (48.i%) for one–6 days and 84 (32.1%) for <24 hours.

Responding to all three surveys was associated with being older, less cigarette dependant, primiparous, in a planned pregnancy and existence a 'recent ex-smoker' at the kickoff of the report (table 1).

Table 1

Comparing of participants who completed all three questionnaires with those who completed either one or ii questionnaires

Characteristic	Completed all follow-upwardly surveys, n=397 (46.vii%)	Did non complete all surveys, n=453 (53.iii%)	P value
	n (%)	north (%)
Weeks' gestation (mean, SD)	15.eight (4.1)	15.4 (4.1)	0.xiv
Historic period, years (hateful, SD)	26.five (five.6)	25.2 (v.v)	<0.001***
Baseline smoking condition
Current smoker	199 (50.1)	289 (63.8)
Ex-smoker	198 (49.ix)	164 (36.two)	<0.001***
Previous pregnancy
Non been significant before	143 (36.0)	132 (29.1)
Been pregnant before	250 (63.0)	314 (69.3)	0.037*
Partner smoking
Partner is not a current smoker/no partner	158 (39.eight)	187 (41.three)
Partner is a electric current smoker	236 (59.4)	263 (58.2)	0.67
Current smokers only
Reported quit attempt since learning of pregnancy/previous questionnaire/birth of infant†
Yep	115 (57.8)	157 (54.3)
No	78 (39.2)	122 (42.2)	0.47
Heaviness of Smoking Alphabetize
Low dependence (0–2)	140 (seventy.4)	170 (58.8)
Moderate dependence (3–4)	46 (23.1)	100 (34.vi)
High dependence (v–6)	1 (0.5)	vii (2.iv)	0.004*

Figure 2 shows a preliminary descriptive analysis of smoking behaviour across pregnancy inside the 397 participants who returned all three questionnaires and illustrates variability in individual's smoking behaviour. Of note, 13.5% (5/37) of women who had stopped smoking in the 3 months before pregnancy were smoking again three months after childbirth, whereas 34.2% (55/161) of women who reported that they had quit after finding out they were pregnant had returned to smoking iii months postpartum. As these information are non adjusted for not-response at follow-up, they may not be consequent with adjusted figures reported below.

Change in smoking behaviour between early pregnancy, late pregnancy and postpartum amongst respondents to all 3 questionnaires (due north=397).

Table 2 shows findings from univariable and multivariable analyses that investigated factors associated with baseline current smokers having reported making a quit try earlier in pregnancy. Every bit these analyses but used baseline data, adjustment for attrition was non needed. Afterward the multivariable modelling, iv factors were independently associated with reporting previous quit attempts at baseline: smoking fewer daily cigarettes, agreeing that smoking during pregnancy can seriously harm the baby, being primiparous and having a planned pregnancy.

Table ii

Univariableand multivariable associations with previous quit attempts in pregnancy at baseline

Variable	Univariable model				Multivariable model
	Current smokers in each response category, due north	Women who made a quit endeavor, n (row %)	OR (95% CIs)	P value	OR (95% CIs)	P value
Historic period, years
<20	97	64 (66.0)	1.00
21–25	179	101 (56.4)	0.63 (0.37 to one.07)
26–xxx	123	57 (46.3)	0.42 (0.24 to 0.74)	0.026
Over 31	86	48 (55.viii)	0.64 (0.35 to 1.xix)
Historic period (years) mean (SD)	25.3 (5.4)	24.9 (v.seven)	0.97 (0.94 to ane.01)	0.xi
General health
Excellent	68	45 (66.2)	1.00
Proficient	348	178 (51.2)	0.49 (0.28 to 0.87)
Fair	68	47 (69.1)	0.95 (0.46 to 1.97)	0.016
Poor	2	1 (l.0)	0.44 (0.03 to vii.five)
Qualifications held
None	121	50 (41.iii)	1.00
GCSEs or above	367	222 (60.5)	2.27 (1.49 to 3.46)	0.0001
Previous pregnancy
Yes	346	169 (48.eight)	one.00		1.00
No	137	101 (73.7)	3.17 (2.02 to 4.98)	<0.0001	2.20 (ane.33 to three.66)	0.0019
No of cigarettes smoked per day
≤5	191	136 (71.2)	i.00		1.00
half-dozen–x	151	86 (57.0)	0.56 (0.36 to 0.88)	<0.0001	0.65 (0.39 to i.07)
≥xi	131	45 (34.4)	0.22 (0.xiv to 0.36)		0.28 (0.xvi to 0.48)	<0.0001
HSI
Low dependence	310	196 (63.ii)	i.00
Moderate dependence	146	61 (41.eight)	0.43 (0.29 to 0.64)	<0.0001
High dependence	8	ii (25.0)	0.19 (0.04 to 0.98)
Urge to fume in last 24 hours
No urges	23	xiv (60.nine)	1.00
Urges	447	251 (56.2)	0.97 (0.42 to 2.24)	0.95
Strength of urges to smoke in concluding 24 hours
No urges	31	16 (51.6)	1.00
Weak	334	194 (58.one)	1.28 (0.60 to two.70)	0.82
Strong	103	59 (57.3)	1.26 (0.55 to 2.86)
Partner smoking condition
Not-smoking partner	111	57 (51.4)	1.00
Smoking partner	334	189 (56.6)	0.88 (0.57 to 1.37)	0.50
No partner	41	26 (63.4)	ane.38 (0.69 to 2.73)
Home ownership
Rent/other	427	234 (54.8)	1.00	0.47
Own home	57	35 (61.4)	1.23 (0.70 to two.17)
Electric current employment
Not in current paid work	324	163 (50.three)	i.00	0.0005
In current paid piece of work	164	109 (66.5)	2.01 (1.35 to 2.99)
Usual occupation
Transmission/not applicable	351	194 (55.3)	1.00	0.13
Non-manual	75	46 (61.iii)	1.50 (0.88 to ii.57)
Ethnicity
White British	447	250 (55.9)	1.00
Other	39	21 (53.9)	one.05 (0.53 to 2.x)	0.88
Timing of pregnancy
Planned	171	110 (64.3)	ane.00		1.00
Surprise	312	158 (50.vi)	0.59 (0.40 to 0.87)	0.007	0.53 (0.34 to 0.82)	0.0045
Felt depressed or hopeless in concluding month
Yes	144	88 (61.1)	1.00	0.21
No	338	181 (53.6)	0.77 (0.52 to 1.16)
Long-term disability or mental illness
Yep	66	34 (51.5)	1.00
No	416	234 (56.3)	ane.25 (0.74 to two.xi)	0.41
Smoking during pregnancy can harm your babe
Disagree	211	81 (38.four)	one.00		1.00
Agree	266	183 (68.eight)	iv.08 (2.76 to 6.02)	<0.0001	4.23 (2.76 to six.48)	<0.0001
Self-efficacy in quitting
Low	412	220 (53.4)	ane.00
Loftier	47	35 (74.5)	iii.72 (1.68 to 8.21)	0.001

At baseline, smokers reported making a median (IQR) of two (one–3) quit attempts lasting at least 24 hours since discovering they were pregnant; in later on pregnancy, 2 (one–5) quit attempts were reported since completing the first questionnaire, and in the postpartum, 2 (1–iv) quit attempts were reported since childbirth (unadjusted data). The median number of quit attempts fabricated by those who smoked across their pregnancy (smokers who completed both baseline and late pregnancy questionnaires, n=177) was three (IQR 1–6); these data were highly skewed with a range of 0–60 24 hours quit attempts reported.

Table iii shows data on smoking rates, quitting behaviour and quit intentions at the three time points adjusted for not-response, every bit appropriate, using multiple imputation; raw (unadjusted) data are included for reference in(supplementary appendix table s1). Adapted figures evidence no evidence that smoking rates inverse in pregnancy; the proportion of smokers was 57.4% (95% CI 54.one to 60.7) at baseline and 59.ane% (95% CI 54.9 to 63.4) in late pregnancy. Notwithstanding, by three months postnatally, the adapted proportion of current smokers was 67.1% (95% CI 62.7 to 71.5). Over half (55.7%, 95% CI 51.3 to 60.1) of smokers reported making quit attempts since becoming pregnant and 51.3% (95% CI 44.seven to 58.0) did then between early and tardily pregnancy; nonetheless, only 27.4% (95% CI 21.vii to 33.2) reported trying to cease afterward childbirth. The proportion of women who intended to effort quitting within the side by side month fell as pregnancy progressed from 40.4% (95% CI 36.ane to 44.8) at baseline to 29.7% (95% CI 23.8 to 35.six) in late pregnancy and just 14.2% (95% CI 10.0 to 18.3) postpartum.

Table 3

Smoking behaviours reported in pregnancy and the postpartum adjusted for non-response at late pregnancy and 3 months postpartum using multiple imputation

Feature	Baseline (early pregnancy)			Late pregnancy		Postpartum
	n	%	95% CI	%	95% CI	%	95% CI
Electric current smokers*	488	57.four	54.1 to sixty.7	59.1	54.9 to 63.iv	67.one	62.vii to 71.5
Reported quit try since learning of pregnancy/previous questionnaire/nascency of baby†
Yes	272	55.7	51.3 to 60.ane	51.3	44.7 to 58.0	27.4	21.seven to 33.2
No	200	41.0	36.vii to 45.four	48.7	42.0 to 55.3	72.6	66.8 to 78.iii
If have fabricated a quit endeavour, attempt lasted at least 24 hours
Yes	178	65.4	59.6 to 71.0	78.9	71.6 to 86.2	67.8	55.8 to 79.8
No	90	33.i	27.7 to 38.9	21.one	13.8 to 28.iv	32.two	20.2 to 44.ii
Cigarettes per day
0–ten	342	lxx.1	65.9 to 74.0	68.3	63.2 to 73.3	60.0	54.3 to 65.7
≥eleven	131	26.8	23.i to 31.0	31.6	26.six to 36.vii	40.0	34.three to 45.vii
How before long after waking smoke first cigarette, min
≤30	260	53.three	48.viii to 57.7	48.six	43.1 to 54.2	48.two	41.8 to 54.6
≥31	206	42.2	37.9 to 46.seven	51.four	45.8 to 56.ix	51.8	45.4 to 58.ii
Heaviness of Smoking Index
Low dependence (0–2)	310	63.5	59.1 to 67.7	68.1	62.five to 73.8	65.7	59.i to 72.3
Moderate-to-high dependence (iii–6)	154	32.6	27.6 to 35.eight	31.9	26.2 to 37.5	34.3	27.7 to twoscore.nine
Intention to quit smoking
Intending to quit within adjacent xxx days	197	40.4	36.1 to 44.8	29.7	23.8 to 35.half-dozen	14.2	10.0 to 18.3
Intending to quit inside next 3 months/not seriously planning to quit	252	51.6	47.2 to 56.i	lxx.three	64.4 to 76.2	85.viii	81.vii to 90.0
Urges to smoke
How often felt urges to smoke in previous 24 hours
No/few urges/don't know	707	83.ii	80.5 to 85.5	82.0	78.7 to 85.three	78.vii	74.8 to 82.6
Frequent urges (a lot of the time-all of the fourth dimension)	135	15.ix	13.6 to xviii.v	18.0	fourteen.7 to 21.3	21.3	17.four to 25.2
Forcefulness of urges to smoke in previous 24 hours
No urges/slight-to-moderate urges/don't know	738	86.eight	84.4 to 88.9	82.8	79.0 to 86.5	83.0	79.0 to 87.0
Strong-to-extremely strong urges	109	12.8	10.7 to fifteen.2	17.ii	xiii.5 to 21.0	17.0	thirteen.0 to 21.0

Adjusted data show some differences in the rates of women restarting smoking according to when they report that they initially quit. Among women who had either not smoked in the 3 months before pregnancy or during early on pregnancy (before completing the baseline questionnaire), 10.two% (95% CI 6.five to 13.9) reported smoking on the tardily pregnancy questionnaire and 31.2% (95% CI 25.2 to 37.2) did and so at 3 months postpartum. All the same, if this information is broken down further, for those who said they quit prior to becoming pregnant, only two.five% reported smoking by tardily pregnancy and 17.8% (95% CI 6.ane to 29.5) reported smoking 3 months postpartum. Whereas, of those who reported quitting after finding out they were meaning (merely before completing the baseline questionnaire), eleven.6% (95% CI 7.3 to xv.9) were smoking past late pregnancy and 34.4% (95% CI 27.6 to 41.2) were smoking iii months postpartum. By comparison, amid smokers at baseline who reported not smoking in late pregnancy, 42.9% (95% CI 24.6 to 61.3) were smoking 3 months after delivery. Overall, of women who reported abstinence on the late pregnancy questionnaire, 26.ii% (95% CI 20.3 to 32.2) had relapsed by 3 months mail service delivery.

Give-and-take

To our knowledge, this is the first study to use prospectively collected, longitudinal information to quantify changes in smoking behaviour through the exam of multiple quit attempts and women's intention to quit during pregnancy and postnatally. Despite over 50% of smokers reporting quit attempts across all three trimesters, there was no show that overall smoking rates changed between joining the study at around viii–24 weeks' gestation and late pregnancy. In smokers, intention to quit inside the next month fell as the pregnancy progressed, and then roughshod further postpartum. Within 3 months of giving birth, around ane third of women who accomplished forbearance earlier or during early pregnancy had returned to smoking. All the same, we observed a trend, not previously reported in longitudinal data, whereby those who quit earlier pregnancy may be less likely to return to smoking postpartum than those that quit on learning of their pregnancy; those that merely achieved forbearance in late pregnancy appeared to be almost likely to return to smoking postpartum. Women's motivation to effort quitting was lowest in the first 3 months following childbirth; merely around a quarter tried quitting during this fourth dimension and far fewer reported intending to quit in the firsthand time to come than had done so at either pregnancy time bespeak.

The originality of this report is a key strength. As previously mentioned, we could discover relatively few observational studies in which meaning women's smoking behaviours were longitudinally recorded at more than one fourth dimension betoken in pregnancy.^{12 xiii 15 sixteen xix–23} Only two of these longitudinal studies followed women up postpartum,^{12 xiii} just four reported whatsoever data on fluctuations or trajectories in smoking status^{12 13 xv 16} and none evaluated multiple quit attempts, ofttimes assessing only heaviness of smoking or successful versus unsuccessful quitting. All other studies investigating individuals' changes in smoking behaviour in pregnancy accept asked most this retrospectively later on pregnancy or at just one time point, and in dissimilarity, nosotros collected longitudinal data during and after pregnancy. We particularly focused on quit attempts and quitting intentions, rather than purely on smoking condition at different time points, and are non aware of any other longitudinal studies that have attempted this. In improver, for the first fourth dimension, we have reported 'attrition-adjusted' rates of smoking or quitting in later pregnancy and postpartum. If we had but used cross-sectional data, we might have underestimated the proportion of smokers in after pregnancy and in the postpartum. We believe that nosotros present the nearly robust bachelor data documenting changes in smoking condition and quitting behaviours across pregnancy and into postpartum, for women who are not participating in an intervention written report.

A limitation is that, although we followed women longitudinally, at each data drove point, nosotros relied on cocky-reported data and recall of smoking behaviour in the immediate past, so we cannot be completely sure that reports are valid. However, a number of factors should have minimised any misreporting of smoking behaviour: no intervention was tested and there was no expectation that participants should attempt stopping; researchers emphasised that responses were of interest irrespective of smoking status and, as women completed questionnaires at three stages, they did non have to recollect their behaviour over long periods. Additionally, studies looking at both self-study and biochemically validated smoking data suggest that self-reported smoking can be both accurate and reliable.^{16 41} It is possible that pregnant women who were concerned about the stigma of smoking may have avoided participation; nosotros do not know how this might take affected findings, but women who consented to join the cohort had similar characteristics to those who declined.²⁴ As the survey was conducted in only two Nottingham hospitals, it is hard to say how far findings can be generalised. To assist assess generalisability, we included survey items that permitted comparison with previous studies; nosotros found our participants who connected to smoke in early pregnancy were similar to pregnant smokers enrolled in other major UK cohorts.²⁴ This suggests that the master findings may employ to pregnant smokers in the UK generally. Likewise, although absolute smoking rates and smoking cessation communication and treatment may vary, pregnant smokers from other high-income countries generally have similar characteristics to those in the Great britain.^{28 42 43} Therefore, it could be considered reasonable to extrapolate many of our findings to pregnant smokers in high-income countries more often than not. Although we had very high rates of eligible women joining the cohort, a further limitation was that attrition was relatively high, with response rates to the two later questionnaires of sixty% and 56%. This is a mutual problem with longitudinal studies,⁴⁴ and as immature, pregnant smokers were likely to exist a particularly hard group to maintain contact with, we used a number of recommended methods to try to maximise response rates.^{24 44 45} However, rather than only relying on incomplete data, nosotros have tried to accost non-response bias past adjusting later on surveys' findings using multiple imputation. In addition, differences in characteristics between the whole cohort and those that responded to all three surveys (table ane) need to exist considered when viewing the unadjusted smoking 'trajectory' analysis shown in figure two. Finally, nosotros assessed smoking status at iii months postpartum, and information technology is probable that some women who were abstemious at this point will have returned to smoking later on this.^{17 18}

The finding that most women in our cohort had quit in the early on stages of pregnancy (before joining the written report) and that smoking rates did non modify between the second trimester and 36 weeks' gestation is consistent with cross-exclusive estimates for smoking prevalence obtained in a big Usa study, which reported these by month of pregnancy.⁴⁶ In that study, smoking prevalence at ane month of gestation was 26%, then betwixt the 4th and eighth month of gestation, smoking rates for each calendar month were 13%–14%.⁴⁶ Other retrospective studies take establish that most women who successfully quit are likely to achieve this soon subsequently finding out they are significant,^{5 47} often inside the first few days.⁴⁷ Many quit spontaneously after discovering they are meaning.⁴⁸ Therefore, it seems that, afterward the early stages of pregnancy, despite even so reporting quit attempts, women'southward smoking behaviour really undergoes very little change.

One written report found that 70% of pregnant women making their first quit try did and then in their outset trimester; however, these information were collected upwards to five years after delivery and only considered first quit attempts.¹⁵ We found that some women made multiple quit attempts throughout pregnancy and we have previously reported that, at baseline, most reported cutting downward or only smoking occasionally since condign pregnant with less than 8% of our accomplice saying that they smoked the aforementioned or more than earlier pregnancy.²⁴ Although cocky-reported, this reinforces findings from qualitative studies, which indicate that many persistent smokers report deliberate, and sometimes detailed, plans to cutting down in their pregnancy, seeing this equally a positive stride and oftentimes equally a route to quitting.⁴⁹ Far fewer women reported making quit attempts in the 3 months after childbirth than they did during pregnancy. Even in early on pregnancy, around half of women had no intention to quit within the side by side 30 days; intention to quit in the curt term was even lower in late pregnancy and was everyman of all postpartum. This diminishing intention to quit has not been reported before and could be considered when designing and delivering cessation interventions; for example, before intervention may be more successful.

We found that women who were primiparous, smoked fewer cigarettes per day, had a planned pregnancy and believed smoking during pregnancy could seriously harm their baby were more than likely to take fabricated a quit attempt during early pregnancy. These findings are comparable to previous literature examining the characteristics of pregnant smokers who successfully achieve abeyance. Primiparous women have previously been found to exist more likely to successfully quit smoking.^{28 29 31 32} This may be because women who have smoked throughout a previous pregnancy without experiencing complications may view the risks of smoking during pregnancy differently to primiparous women, and therefore exist less motivated to make a quit attempt.²⁹ Similarly, previous studies have found that heavier smoking is negatively associated with successfully quitting in pregnancy,^{29 31 33} and heavier smokers are less likely to accept high motivation to quit during pregnancy.³³ Women whose pregnancies are unintended take previously been establish to be more likely to continue smoking during pregnancy,^{28 35–37} and also, pregnant smokers who do non report business concern virtually the effect smoking might have on the wellness of their unborn baby were more likely to accept low motivation to quit smoking.³³ These findings place women who are nearly likely to make a quit attempt and will potentially benefit the most from National Health Service support. Heavier smokers and women in 2nd or later and unplanned pregnancies who are less likely to attempt quitting may require unlike, more than intensive or tailored forms of back up.

Implications for do

Although our data advise that motivation to quit may be strongest in early pregnancy, some women will exist receptive to quitting at any time, every bit indicated by their multiple quit attempts throughout pregnancy, and this confirms that it is important to discuss smoking with women at every appointment and to refer them for stop smoking support.⁹ One rather surprising finding was that, in early pregnancy to mid-pregnancy, 44% (211/477) of smokers disagreed that smoking in pregnancy can harm their baby; as those who agreed with this argument were more probable to accept made previous quit attempts at baseline, boosted education on this effect should be considered by health professionals. Preventing resumption of smoking after pregnancy is a disquisitional public health result; if women restart, their lifelong health is at adventure and their infants are more likely to be exposed to secondhand smoke^l and to eventually get smokers.⁵¹ Women frequently need assistance to resist returning to smoking later on childbirth, but there are currently few effective interventions for this.⁵² Women appear to be more inclined to consider quitting during pregnancy than in postpartum, and this is important when designing interventions. A potential reason for restarting smoking and for making fewer quit attempts postpartum may be that women perceive that harm to the baby from smoking is much higher during pregnancy compared with after delivery. Notwithstanding, some postpartum women do make quit attempts or may be planning to quit in the medium term, so engaging with them again after birth, to call up about planning for this in the medium term, rather than immediately, might be a successful selection. Previous studies take shown that women who quit spontaneously early in pregnancy are likely to be different and more successful than those who quit later,⁴⁸ and we found that women appear to exist more than likely to return to smoking after childbirth the later on in pregnancy they quit. Therefore, exploring potential reasons for this, for case, demographic factors or women's intentions, could help to identify if dissimilar women may do good from culling approaches to help foreclose relapse, perhaps past developing more tailored interventions. Although quit attempts might suggest receptivity to quitting, what is non well understood is how interest in smoking abeyance back up may modify during pregnancy.

Conclusions

Many pregnant women who smoke attempt quitting throughout their pregnancy, but this makes little difference to overall smoking rates. After giving birth, most smokers seem less inclined to make further quit attempts and many who quit in early pregnancy return to smoking. Women who quit in belatedly pregnancy may be almost likely to return to smoking after childbirth, while those who stopped prior to pregnancy may be least likely to relapse. It is therefore imperative to discuss smoking with women, including recent ex-smokers, throughout pregnancy and postpartum, and to go along to offer and provide specialist terminate smoking support.

Supplementary Fabric

Acknowledgments

The authors would like to thank all participants and staff involved in this study and Nottingham University Hospitals NHS Trust for facilitating this enquiry. Nosotros also thank James Brimicombe for developing the study database and Rachel Whitemore for her invaluable help with this report.

Footnotes

Contributors: SC helped to excogitate the study, fabricated a substantial contribution to the development of the protocol and questionnaires, assisted with day-to-solar day troubleshooting during the data drove phase and drafted and revised this manuscript. SO helped to design the information drove process, recruited participants into the accomplice, managed the twenty-four hours-to-twenty-four hour period running, assisted with data analysis and contributed to the drafting of this manuscript. JL-B contributed to the development of the study protocol and questionnaires, advised on analysis and contributed to the training of this manuscript. EB undertook the analyses and estimation of data in table 2 equally function of a Bachelor of Medical Sciences project and contributed to the preparation of this manuscript. LV assisted with data analysis and interpretation and contributed to the preparation of this manuscript. KB helped to blueprint the data collection process, recruited participants into the cohort, managed the solar day-to-day running and contributed to the preparation of this manuscript. FN, MU, KEP and SS all contributed to the development of the study protocol and questionnaires, contributing expertise from their own detail noesis base, and to the preparation of this manuscript. TC conceived the study and made substantial contributions to the development of the report protocol and questionnaires and to the preparation of this manuscript. All authors read and approved the final manuscript. Rachel Whitemore assisted with study administration, phone follow-ups and data entry.

Funding: This commodity presents contained inquiry funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (grant number RP-PG 0109-10020). The views expressed in this paper are those of the authors and not necessarily those of the National Health Service, the NIHR or the Department of Health. SC, SO, JL-B, KB, FN, MU, SS and TC are members of the Great britain Centre for Tobacco and Booze Studies (UKCTAS), a Great britain Clinical Research Collaboration Public Health Enquiry Centre of Excellence. UKCTAS receives core funding from the British Heart Foundation, Cancer Research UK, Economic and Social Inquiry Council, Medical Inquiry Council and the Section of Health under the auspices of the Great britain Clinical Research Collaboration. SC, And so, KB, SS and TC are members of the NIHR School for Primary Care Research. TC acknowledges the support of the NIHR Collaboration for Leadership in Applied Health Enquiry.

Competing interests: KEP is a trustee of The Equality Trust (a registered charity) and receives occasional honoraria, all of which are donated to The Equality Trust or for educatee support at the University of York. In the last 5 years, TC has been paid honoraria on 2 occasions for speaking at meetings or conferences organised by Pierre Fabre Laboratories (a nicotine replacement therapy manufacturer).

Ethics approval: Derbyshire Research Ethics Proportionate Review Sub-Committee gave ethical approval.

Provenance and peer review: Non commissioned; externally peer reviewed.

Data sharing statement: The dataset is still subject area to farther analyses. Relevant anonymised information available from the authors on reasonable request.

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