Spontaneous quitting: Self-initiated smoking cessation in early pregnancy

Transcription

1 Nicotine & Tobacco Research Volume 6, Supplement 2 (April 2004) S203 S216 Review Spontaneous quitting: Self-initiated smoking cessation in early pregnancy Laura J. Solomon, Virginia P. Quinn [Received 2 December 2002; accepted 18 April 2003] This article reviews the empirical literature on spontaneous quitting of cigarette smoking among pregnant women. We define spontaneous quitting and discuss its prevalence and the characteristics that differentiate spontaneous quitters from women who continue to smoke during pregnancy. We examine the success of these women in abstaining throughout their pregnancy, and their pattern of relapse back to smoking during the postpartum period. We review studies that have tested strategies to maintain abstinence among spontaneous quitters, and we conclude the article with gaps identified in the literature that warrant further study. Introduction Pregnancy is a time of great change. For many women, becoming pregnant serves as a catalyst to modify their health practices in order to enhance the development of the fetus. For example, concerns about fetal alcohol syndrome lead many women to forgo alcohol during pregnancy (Bruce, Adams, Shulman, & Martin, 1993; Durham et al., 1997; Kruse, Le Fevre, & Zweig, 1986; Ockene et al., 2002). Similarly, many women who smoked cigarettes prior to conception quit on their own shortly after becoming pregnant. These women are referred to as spontaneous quitters. Spontaneous quitters are worthy of attention because they are remarkably successful at abstaining throughout pregnancy. With no or little formal intervention, 65% 81% of spontaneous quitters are biochemically confirmed abstinent at the end of pregnancy, up to 6 months after quitting (Ershoff, Quinn, & Mullen, 1995; Lowe, Windsor, Balanda, & Woodby, 1997; McBride et al., 1999; Panjari et al., 1997; Secker-Walker et al., 1995; Secker-Walker, Laura J. Solomon, Ph.D., Department of Psychology, University of Vermont, Burlington, VT; Virginia P. Quinn, Ph.D., Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA. Correspondence: Laura J. Solomon, Ph.D., Department of Psychology, Dewey Hall, University of Vermont, 2 Colchester Avenue, Burlington, VT USA. Tel: z1 (802) ; Fax: z1 (802) ; laura.solomon@uvm.edu Solomon, Flynn, Skelly, & Mead, 1998; Sexton, Hebel, & Fox, 1987). In contrast, a group of nonpregnant, male and female smokers who quit abruptly on their own for at least 48 hours had a 24% success rate at 6 months postcessation (Hughes et al., 1992). Outcomes from eight self-help cessation studies of nonpregnant smokers revealed a median pointprevalence abstinence rate of 13% at 6 months (Cohen et al., 1989). Even in highly motivated, symptomatic populations, such as post myocardial infarction patients, the abstinence rates are around 45% at 6 months after the myocardial infarction (Dornelas, Sampson, Gray, Waters, & Thompson, 2000; Taylor, Houston-Miller, Killen, & DeBusk, 1990), considerably lower than the rates found among pregnant spontaneous quitters over a comparable time period. This finding raises questions about the attributes and skills of these women that might account for their unique success. In addition to their success at abstaining throughout pregnancy, spontaneous quitters distinguish themselves by their ability to make multiple health behavior changes simultaneously (Pirie, Lando, Curry, McBride, & Grothaus, 2000). Many pregnant women shift their dietary practices as well as their alcohol and caffeine consumption during pregnancy. However, most formal smoking cessation programs have observed better success when abstinence for smoking alone is the targeted goal and fewer demands for other ISSN print/issn X online # 2004 Society for Research on Nicotine and Tobacco DOI: /

2 S204 SPONTANEOUS QUITTING behavior changes, such as dietary restrictions, are placed on participants (Hall, Tunstall, Vila, & Duffy, 1992; Pirie et al., 2000). Clearly, the motivation to have a healthy infant fosters the multiple behavior changes rarely observed in other circumstances, and social support from family and friends during the pregnancy may rally the environment around this common goal. Yet, ultimately, the women themselves must initiate and maintain the behavior changes, and it is worth noting that so many do so. One of the most intriguing observations about these spontaneous quitters is that despite their success at abstaining throughout pregnancy, most relapse by 6 months after delivery (Hajek et al., 2001; Mullen, Richardson, Quinn, & Ershoff, 1997). This finding represents a rare pattern among smokers in that most relapses occur early after a quit attempt and far less frequently after prolonged abstinence (Hughes et al., 1992; Zhu, Melcer, Sun, Rosbrook, & Pierce, 2000). Yet spontaneous quitters, many of whom quit for the pregnancy and not for their own health, tend to return to smoking after the pregnancy ends, just as many women resume their alcohol consumption after delivery. Although breast feeding may be associated with postpartum abstinence (Mullen et al., 1997), the resolve to remain abstinent seems to diminish, and relapses occur in 61% 76% of spontaneous quitters during the postpartum period (Hajek et al.; Mullen et al.). For an in-depth examination of the factors that influence postpartum relapse, see the article by Mullen in this issue of Nicotine & Tobacco Research. In this article, we define spontaneous quitters and discuss their prevalence and characteristics as well as their successes and failures in maintaining abstinence throughout pregnancy and beyond. Although the topic is important, the empirical literature on spontaneous quitters is fairly modest, and variations in sample characteristics and methodological rigor limit our ability to draw many conclusions. At the beginning of each section, we mention some of the limitations of the existing literature, and at the end of the article, we highlight areas that warrant further investigation. Definition and prevalence of spontaneous quitting We define a spontaneous quitter as a woman who reports quitting on her own after finding out she is pregnant and before she receives advice or intervention from her prenatal care providers. This definition is narrow in that it applies only to pregnant women. It also is somewhat arbitrary, because women begin prenatal care at different weeks of pregnancy, may have sought help with cessation before starting prenatal care, and may quit smoking later in pregnancy with or without provider assistance. Nevertheless, spontaneous quitters, as we have defined them, comprise the majority of women who stop smoking during pregnancy. Some researchers label these women early or recent quitters instead of spontaneous quitters (Kendrick et al., 1995; Lowe et al., 1997; McBride et al., 1999), because most women begin prenatal care in the first trimester of pregnancy (Lewis, Mathews & Heuser, 1996) and up to 17% of those still smoking at intake may stop sometime before delivery (Mullen, 1999; Windsor, Boyd & Orleans, 1998). However, spontaneous quitters differ significantly in their pregnancy and smoking histories from women who are still smoking at the start of prenatal care. Their experience with cessation and abstinence offers valuable lessons for prenatal and postpartum smoking interventions. Few national reports exist on the prevalence of spontaneous quitting during pregnancy. Kleinman and Kopstein (1987) analyzed pregnancy-related smoking behavior collected 6 9 months after delivery from two national samples of married mothers with live births in 1967 and Data revealed that 11% 17% of both White and Black mothers who smoked prior to pregnancy reported no daily smoking after they found out they were pregnant. Fingerhut, Kleinman, and Kendrick (1990) examined responses to a follow-up to the 1985 National Health Interview Survey among married White women aged years who were currently pregnant or whose most recent birth occurred during the preceding 5 years. Twenty-seven percent of the smokers reported quitting when they found out they were pregnant. Most recently, LeClere and Wilson (1997) presented results from the 1990 National Health Interview Survey on Health Promotion and Disease Prevention, which included women aged years who had a live birth in the preceding 5 years and were not pregnant at the time of the survey. Among women who smoked prior to becoming pregnant, 23% said they stopped smoking altogether after learning of their pregnancy. These national prevalence reports are limited by the characteristics of the respondents. For example, unmarried women are more likely to smoke than are married women (LeClere & Wilson, 1997). Of further concern, retrospective reports of smoking behavior during pregnancy are subject to imprecise estimates of when cessation occurred and, therefore, may include women who stopped smoking later in pregnancy. Smoking histories obtained at the start of prenatal care should be less influenced by inaccurate recall. A review of the literature finds a consistently lower rate of spontaneous quitting among U.S. women receiving care in public maternity clinics compared with women who have private insurance. Rates as low as 11% and 15% were reported by Kendrick et al. (1995) and Windsor et al. (1993), respectively, among women in public maternity clinics. More commonly, the prevalence of spontaneous quitting in health care settings

3 NICOTINE & TOBACCO RESEARCH S205 serving lower income women ranges between 20% and 28% (Kendrick et al.; Ockene et al., 2002; Secker- Walker et al., 1998; Windsor et al., 1985). Similar rates have been found in public maternity clinics in Sweden (Cnattingius, 1989; Cnattingius, Lindmark, & Meirik, 1992; Hakansson, Lendahls, & Petersson, 1999), Norway (Haug, Aaro, & Fugelli, 1992), the United Kingdom (Hajek et al., 2001; MacArthur, Newton, & Knox, 1987), and Australia (Panjari et al., 1997). In contrast, in U.S. managed health care organizations serving mainly privately insured women, spontaneous quit rates are more than twice as high, ranging from 40% to 65% (Aaronson, Ershoff & Danaher, 1985; Ershoff et al., 1995, 1999; McBride et al., 1999; Petersen, Handel, Kotch, Podedworny, & Rosen, 1992; Saks et al., 2001). Rates of spontaneous quitting are usually based on pregnant women s reports of smoking behavior at the start of prenatal care. Yet, three of four studies that biochemically confirmed reports of spontaneous quitting at pregnancy intake found substantial overreporting of cessation. In a study of women attending a public maternity clinic in Australia, Panjari et al. (1997) observed that 20% of selfdeclared spontaneous quitters had urinary cotinine values inconsistent with abstinence. Similarly, in two studies among privately and publicly insured pregnant women, Secker-Walker and colleagues (1995, 1998) found that 17% 21% of spontaneous quitters had elevated urinary cotinine values at their first prenatal visit. Ockene and colleagues (2002), by contrast, observed that only 9% of low-income spontaneous quitters had salivary cotinine results indicative of smoking. Thus, a 10% 20% false-negative rate appears to exist among women who report quitting smoking early in their pregnancy. The effects of maternal smoking on fetal health have been widely disseminated over several decades, and the social demand for abstinence during pregnancy is high. Fear of social stigma and strong desire to stop smoking probably account for much of the difference between self-reports and biochemical assessments of spontaneous quitting. However, differences between subjects self-reports and biochemical assessments across studies may be due to factors such as the sensitivity and specificity of biochemical tests (Boyd, Windsor, Perkins, & Lowe, 1998) and cotinine cutoff levels used to determine smoking status (Panjari et al., 1997). Differences also may be a function of varying definitions of spontaneous quitting. For example, Panjari et al. and Ockene et al. (2002) required reports of at least 7 days of abstinence for a subject to be classified as a spontaneous quitter. In contrast, the Secker-Walker et al. studies (1995, 1998) included as spontaneous quitters women who were smoking less than an average of one cigarette per day in the previous week. Finally, differences may reflect subjects awareness that a biochemical assessment will be made subsequent to their self-report. Knowledge of subsequent testing can enhance accuracy of smoking disclosure (Roese & Jamieson, 1993). Evidence of the threat to fetal and child health from maternal smoking has continued to grow since early reports in the mid-1960s (U.S. Department of Health and Human Services, 2001). However, few data are available to determine changes in rates of spontaneous quitting over time. Between 1987 and 1996, the prevalence of smoking during pregnancy decreased from 16% to 12%, according to results from the Behavioral Risk Factor Surveillance System survey conducted in 33 states (Ebrahim, Floyd, Merritt, Decoufle, & Holtzman, 2000). However, after comparing rates of smoking initiation and current smoking among women of childbearing age, Ebrahim and associates concluded the decline reflected a reduction in smoking initiation rather than an increase in cessation during pregnancy. Characteristics of spontaneous quitters Eleven published studies have compared the characteristics of spontaneous quitters and women who were still smoking at the start of prenatal care. These studies were conducted among privately and publicly insured women in the United States and public maternity patients in Australia, Sweden, and the United Kingdom. Results from these studies may have been influenced by the specific characteristics measured in each study and whether multivariate analyses were applied. Nevertheless, consistent differences between spontaneous quitters and continuing smokers can be identified across the samples of pregnant women. As displayed in Table 1, spontaneous quitters differ from continuing smokers on demographic characteristics, pregnancy-related factors, smoking histories, smoking environments, beliefs and attitudes, and other psychosocial variables. Most of the studies compared spontaneous quitters and continuing smokers on age, education, and marital/partner status; some included a measure of income. Across these studies, spontaneous quitters had more years of education, compared with continuing smokers (Curry, McBride, Grothaus, Lando & Pirie, 2001; Dejin-Karlsson et al., 1996; Hajek et al., 2001; LeClere & Wilson, 1997; O Campo, Faden, Brown, & Gielen, 1992; Ockene et al., 2002; Petersen et al., 1992), higher incomes (Curry et al., 2001; LeClere & Wilson, 1997; Panjari et al., 1997; Petersen et al.), and were more likely to be married or have a partner (Curry et al.; Dejin-Karlsson et al.; Hajek et al.; LeClere & Wilson, 1997; Panjari et al.; Petersen et al.). Age differences, when observed, were inconsistent across samples (Dejin-Karlsson et al.; LeClere & Wilson, 1997; O Campo et al.). Three studies conducted in prenatal care settings found a higher

4 Table 1. Reference Aaronson et al., 1985 Characteristics of spontaneous quitters compared with women who are smoking at the start of prenatal care. Multivariate analysis Sample size Yes 58 U.S. HMO insured; racially/ethnically diverse Cnattingius, 1989 Yes 673 Swedish public maternity clinics Curry et al., 2001 z No 897 U.S. primarily HMO insured; 90% White Dejin-Karlsson et al., 1996 Sample characteristics Significant associations Nonsignificant associations Pregnancy-related 2a Smoking history 3f Smoking environment 4b Pregnancy-related 2a Smoking history 3a,c Smoking environment 4a,b Demographics 1a,b,c,d Pregnancy-related 2b,d Smoking history 3a,b,d Demographics 1a,b,c,d Pregnancy-related 2b,d Smoking history 3a,c,e Smoking environment 4a Beliefs 5a,b,c,f Not noted Yes 897 Beliefs 5d,e Beliefs 5f Partially 404 Primigravidas in Swedish public maternity clinics Hajek et al., 2001 No 1120 United Kingdom public maternity clinics LeClere & Wilson, No National sample U.S. women with live 1997 birth in past 5 years Ludman et al., 2000 z Yes 819 U.S. primarily HMO insured; 90% White McBride et al., 1998 z No 688 U.S. primarily HMO insured; 90% White O Campo et al., 1992 Demographics 1a(older),c,d Pregnancy-related 2c Smoking history 3f Smoking environment 4b Psychosocial 6a,f,g,h Demographics 1c,d,f,h Smoking history 3b Demographics 1a(younger), b(blacks v. whites, Hispanics v. non-hispanics),c,d,e Smoking history 3a,b Smoking environment 4a,d,e Demographics 1a,b,f Pregnancy-related 2d Smoking history 3e Psychosocial 6d Demographics 1a Not noted Demographics 1a,b,c,d,e,f Pregnancy-related 2c Psychosocial 6b,c Not noted U.S. private and public obstetrical practices Yes 247 White Demographics 1a(younger), c Demographics 1b,d Yes 358 Black Pregnancy-related 2a Ockene et al., 2002 Yes 601 U.S. public maternity clinics; racially/ethnically diverse Panjari et al., 1997 No 599 Australian public maternity clinic Pregnancy-related 2e 1b(Caucasian v. Demographics African-Am),c,g Pregnancy-related 2a Smoking history 3a,b Smoking environment 4a Beliefs 5a Psychosocial 6b Demographics 1d,e,f,h Pregnancy-related 2a,d,e Smoking history 3a,b,e,f,g,h Smoking environment 4a,b Beliefs 5a,b,g,h Psychosocial 6e Pregnancy-related 2e Demographics 1a,b,c,d Pregnancy-related 2a 1a,b(Hispanic v. Demographics non-hispanic),d,f,j Pregnancy-related 2d Pregnancy-related 2d Smoking environment 4c,d Beliefs 5b Psychosocial 6d,e,i Demographics 1a,c,i Pregnancy-related 2b,f S206 SPONTANEOUS QUITTING

5 Table 1. Continued. Reference Multivariate analysis Sample size Sample characteristics Significant associations Nonsignificant associations Petersen et al., 1992 No 317 U.S. HMO insured; racially/ethnically diverse Quinn et al., 1991 Yes 266 U.S. HMO insured; racially/ethnically diverse 1b(Caucasian v. others),c,d,e Demographics Pregnancy-related 2a Smoking environment 4b Pregnancy-related 2d,g Smoking history 3a Smoking environment 4c Beliefs 5a Demographics 1a Smoking environment 4a Demographics 1a,b,c,d Pregnancy-related 2a,b Smoking history 3b,3c Smoking environment 4b Note. HMO~health maintenance organization. 1 Demographics ( a age, b race/ethnicity, c higher education, d married/living with partner, e higher income, f employed, g not born in US, h nonmanual occupation self, i nonmanual occupation partner, j insurance status) 2 Pregnancy-related characteristics ( a primigravida/primipara, b increased nausea/sickness during pregnancy, c planned/desired to be pregnant, d earlier entry into prenatal care, e intending to breastfeed, f prepregnancy weight, g previous miscarriage) 3 Smoking history characteristics ( a lighter smoker before pregnancy, b longer time to first cigarette of the day, c older when initiated smoking, d quit in previous pregnancy, e more previous quit attempts, f fewer years smoking, g longer previous quits, h less difficulty quitting) 4 Smoking environment ( a nonsmoking partner, b fewer smokers among family/friends, c fewer household members who smoke, d partner support for cessation, e partner trying to quit) 5 Beliefs and attitudes ( a smoking harms fetus/greater concern about fetal health, b smoking harms self/greater concern for own health, c general health beliefs, d lower intrinsic motivation, e lower extrinsic motivation, f pregnancy-related motivation, g greater self-efficacy for abstinence, h fewer temptations to smoke) 6 Psychosocial characteristics ( a less job strain, b lower stress/fewer problems, c fewer depressive symptoms, d abstaining from alcohol, e greater psychological well-being, f more general support, g more partner support, h greater social participation, i more emotional support) z Analyses from randomized trial described by Curry et al., NICOTINE & TOBACCO RESEARCH S207

6 S208 SPONTANEOUS QUITTING proportion of spontaneous quitters among White than Black pregnant women (Ockene et al.; Petersen et al.; Quinn, Mullen, & Ershoff, 1991); however, this finding remained significant in only one of the studies when the analyses controlled for other variables (Ockene et al.). In contrast, retrospective reports from a national survey found Black and Hispanic women were more likely to have stopped smoking spontaneously during pregnancy (LeClere & Wilson, 1997). Bivariate and multivariate analyses across studies consistently found a higher proportion of spontaneous quitters among women having their first child (Aaronson et al., 1985; Cnattingius, 1989; Curry et al., 2001; O Campo et al., 1992; Ockene et al., 2002; Panjari et al., 1997; Petersen et al., 1992; Quinn et al., 1991). Other pregnancy-related factors associated with spontaneous quitting included having a planned pregnancy (Curry et al.; Dejin-Karlsson et al., 1996), entering prenatal care earlier (Panjari et al.; Quinn et al.), experiencing nausea or illness during the first trimester (Curry et al.), intending to breast feed (O Campo et al.; Panjari et al.), and having had a previous miscarriage (Quinn et al.). Perhaps women who are having their first child are more motivated to begin prenatal care sooner and to follow health advice such as abstaining from tobacco and alcohol. The association also may be due to the lower probability of quitting observed among women who smoked during a previous pregnancy (Curry et al.; Dietz, Adams, Rochat, & Mathis, 1997). All studies that included assessments of smoking history found significant differences between spontaneous quitters and continuing smokers on indicators of nicotine addiction. Spontaneous quitters were more likely to be lighter prepregnancy smokers (Cnattingius, 1989; Curry et al., 2001; LeClere & Wilson, 1997; Ockene et al., 2002; Panjari et al., 1997; Quinn et al., 1991) who smoked their first cigarette later in the day (Curry et al.; Hajek et al., 2001; Ockene et al.; Panjari et al.), were older when they began to smoke (Cnattingius, 1989), had smoked for fewer years (Aaronson et al., 1985; Dejin-Karlsson et al., 1996), and had made more previous quit attempts (Panjari et al.). These findings suggest that spontaneous quitters are less addicted smokers who, consequently, have less difficulty quitting. The smoking environment can have an important influence on smoking behavior. The general cessation literature suggests that less exposure to other smokers helps smokers quit and maintain abstinence. Many studies compared spontaneous quitters with continuing smokers on characteristics of their smoking environment. The findings reveal that spontaneous quitters have fewer smokers in their social network and, specifically, are less likely to have a partner who smokes (Aaronson et al., 1985; Cnattingius, 1989; Dejin-Karlsson et al., 1996; McBride et al., 1998; Ockene et al., 2002; Panjari et al., 1997; Petersen et al., 1992; Quinn et al., 1991). Additionally, in a study by McBride and colleagues, spontaneous quitters reported receiving more positive support from their partners for quitting than did continuing smokers. Several studies assessed smoking-related beliefs and attitudes and found that spontaneous quitters, compared with continuing smokers, expressed more concern about the harm to fetal health from maternal smoking (Ockene et al., 2002; Panjari et al., 1997; Quinn et al., 1991). Although harm to maternal health from smoking also was assessed in several studies, it was not significantly associated with spontaneous quitting in a multivariate model (Ockene et al.). Curry and colleagues (2001) examined motivation for smoking cessation among pregnant women in a model that included demographic and pregnancy and smoking history variables. They found both spontaneous quitters and continuing smokers were highly motivated by concern for fetal health and the desire to have a healthy pregnancy. However, spontaneous quitters were less motivated by social pressure and personal health concerns, perhaps because they had already achieved cessation. Panjari et al. (1997) assessed temptations to smoke in situations associated with high risk for smoking. Compared with continuing smokers, spontaneous quitters reported significantly lower temptations to smoke in all situations examined. Unfortunately, studies conducted to date on the influence of beliefs and attitudes on spontaneous quitting are methodologically flawed because they are cross-sectional assessments conducted only after the change in smoking behavior occurred. Thus, results leave unclear whether the beliefs and attitudes preceded or were a function of spontaneous quitting. A few studies explored the relationship between other psychosocial characteristics and spontaneous quitting. Three studies observed that spontaneous quitters were less stressed or reported fewer stressors than continuing smokers (Dejin-Karlsson et al., 1996; Ludman et al., 2000; Ockene et al., 2002); however, with the inclusion of measures of addiction, the relationship became less robust. Others observed that spontaneous quitters had higher levels of psychological well-being compared with women who continued to smoke (Ockene et al.; Panjari et al., 1997) but no differences in depressive symptoms (Ludman et al.). Conflicting results were found on measures of social support (Dejin-Karlsson et al.; Ockene et al.). These studies, like the studies on beliefs and attitudes, assessed the psychosocial characteristic only after cessation had occurred in spontaneous quitters, making it difficult to interpret the findings. In summary, compared with women who continue to smoke in early pregnancy, spontaneous quitters have more education, have higher incomes, and are more likely to be married or have a partner. They are more likely to be having their first child with a

7 NICOTINE & TOBACCO RESEARCH S209 planned pregnancy, and they enroll in prenatal care early. Compared with women who continue to smoke, spontaneous quitters have fewer smokers in their social network and are less likely to have a partner who smokes. They report stronger beliefs in the harm to fetal health from maternal smoking and have a smoking history indicative of a lower level of nicotine addiction. These characteristics suggest that spontaneous quitters face fewer barriers to cessation and may have more resources to support their efforts to achieve and maintain abstinence during pregnancy. Maintenance of abstinence during pregnancy among spontaneous quitters receiving no or minimal intervention How well spontaneous quitters maintain abstinence during pregnancy can be gleaned from observational studies and from the minimal intervention control conditions of relapse prevention trials. As seen in Table 2, the self-reported abstinence rates of spontaneous quitters near the end of pregnancy range from 73% to 87%. When biochemical confirmation is included as a criterion for end-of-pregnancy abstinence, that range in abstinence drops to 65% 81%. In a number of these studies, abstinence may have been enhanced slightly by exposure to a minimal intervention during pregnancy (Ershoff et al., 1995; McBride et al., 1999; Petersen et al., 1992; Secker-Walker et al., 1998). However, most of these studies did not confirm abstinence at baseline, and as can be seen from the study by Panjari and colleagues (1997), sustained abstinence during pregnancy is higher among women who were biochemically confirmed abstinent at baseline. Thus, sustained abstinence among true spontaneous quitters may be at the high end of the range reported, suggesting that these women are extremely successful at abstaining for 6 months or more while pregnant. As seen in Table 2, the maintenance rates do not seem to vary systematically as a function of recruitment from public or private prenatal practices, number of weeks pregnant at the end-of-pregnancy assessment, or whether the data were collected in the 1980s or 1990s. Several studies have investigated characteristics of spontaneous quitters who remain abstinent during pregnancy (Ershoff, et al., 1995; McBride et al., 1998; Petersen et al., 1992; Secker-Walker et al., 1995, 1998). The range of variables examined include (a) demographic characteristics (age, education, race/ethnicity, marital status, income, insurance status), (b) pregnancy history (parity, weeks pregnant at entry into prenatal care, health status), (c) smoking history (age began smoking, prepregnancy smoking rate, previous quit attempts, length of abstinence, exhaled carbon monoxide), (d) beliefs and attitudes about smoking and quitting (belief in harm to fetus, belief in harm to mother, motivation to smoke, confidence to remain abstinent, intention to remain abstinent), and (e) smoking environment (smokers in the social network, smokers in the household, partner smoking status, partner support for cessation). Multivariate analyses of these characteristics indicate that spontaneous quitters who remained abstinent during pregnancy were more likely to be older, college educated, and having their first child, compared with those who relapsed during pregnancy. In terms of smoking history, they were abstinent longer than a week with no slips at baseline and had a lower exhaled carbon monoxide reading at baseline. Additionally, spontaneous quitters who abstained throughout pregnancy had stronger beliefs about the harmful effects of smoking on the fetus, had greater confidence in their ability to remain abstinent, and reported lower motivation to resume smoking. No significant effects on maintenance of abstinence were observed for the smoking environment. These findings present a picture of the successful spontaneous quitter as a well-educated, older woman having her first child who is concerned about the effects of smoking on the fetus and is highly motivated and confident about quitting. Furthermore, she has already experienced some success, having achieved abstinence for at least a week prior to her first prenatal visit. This latter observation may be most critical, because relapses in self-initiated quitters typically occur close to a quit date (Hughes et al., 1992). The fact that she has already abstained for over a week is a good indicator of future success. Conversely, spontaneous quitters who enter prenatal care with less than a week of smoking abstinence behind them may be more vulnerable to relapse and in greater need of assistance. This is especially true of women who report abstinence but who show evidence of smoking on biochemical indicators, because they are about half as likely to be abstinent at the end of pregnancy as biochemically confirmed baseline spontaneous quitters (Secker-Walker et al., 1998). Maintenance of abstinence postpartum among spontaneous quitters The positive portrait of successful maintenance of abstinence among spontaneous quitters during pregnancy fades within 6 months following delivery. Although few studies have examined postpartum relapse exclusively in spontaneous quitters, those that have paint a troubling picture. Most of the data on postpartum abstinence are based on selfreports, and only two studies (Hajek et al., 2001; Mullen et al., 1997) report postpartum outcomes for spontaneous quitters who were abstinent near the end of pregnancy. In the control conditions of relapse prevention trials, 57% of baseline spontaneous quitters

8 Table 2. Maintenance of abstinence during pregnancy among spontaneous quitters (SQs) receiving no or minimal intervention a. Reference Sample size Sample characteristics Minimal intervention Determination of smoking status Ershoff et al., self-reported SQs HMO patients in southern California, Lowe et al., self-reported SQs Public maternity clinic patients in Alabama, McBride et al., self-reported SQs HMO patients in Washington and Minnesota, mid-1990s Panjari et al., self-reported SQs Public prenatal clinic patients 137 confirmed SQs in Australia, 14% quit prior to pregnancy, Petersen et al., self-reported SQs HMO patients in Boston; some could have quit prior to pregnancy, Secker-Walker et al., 1995 Secker-Walker et al., 1998 Sexton & Hebel, 1984; Sexton et al., (of which 54 confirmed SQs) 48 (38 of whom were confirmed SQs) Private and public patients in Vermont, Public maternity clinic patients in Vermont, self-reported SQs Public and private patients in Maryland, smoked w10 cigarettes/day before pregnancy, early 1980s Valanis et al., self-reported SQs Private and public patients in Oregon, Two-page pamphlet, one-page tip sheet from health educator on avoiding relapse Usual prenatal care including nurses advice not to smoke End of pregnancy assessment % Quit Urinary cotinine Third trimester 80% b Salivary thiocyanate 32 weeks 56% c 76% d Mailed self-help booklet Self-report 28 weeks 80% c Assessments only Urinary cotinine 35 weeks 73% d Usual obstetrical care; mailed cessation resources and health education materials Usual care advice by obstetrician/midwife at first prenatal visit Brief advice by obstetrician/midwife at first prenatal visit; relapse pamphlet Self-report Urinary cotinine Self-report Cotinine/creatinine Self-report plus CO Urinary cotinine 82% d 24 weeks 87% d 65% d 36 weeks 83% d 72% d 36 weeks 77% d 81% d No special help about smoking Salivary thiocyanate 32 weeks 75% d Usual care from prenatal staff Self-report One-year after delivery retrospective recall 73% S210 SPONTANEOUS QUITTING Note. HMO~health maintenance organization. CO~carbon monoxide. a Minimal intervention typically reflects the control condition of an intervention study. b Excludes those who moved away and miscarried but includes others who didn t respond to follow-up as smokers. c Includes losses to follow-up as smokers. d Excludes losses to follow-up.

9 NICOTINE & TOBACCO RESEARCH S211 reported abstinence at 2 months postpartum (Petersen et al., 1992), and 49% reported abstinence at 3 months postpartum (Sexton et al., 1987). By 6 months postpartum, abstinence among spontaneous quitters who were not smoking near the end of pregnancy ranged from 24%, based on carbon monoxide verification (Hajek et al.), to 39%, based on selfreport (Mullen et al., 1997). Thus, even exclusively among those spontaneous quitters who were abstinent near the end of their pregnancy, the majority relapsed by 6 months after delivery. Only one study (Mullen et al., 1997) found significant predictors of relapse postpartum among spontaneous quitters who abstained throughout pregnancy. In a multivariate analysis, the significant predictors of postpartum relapse included having a partner who smoked postpartum, having less confidence at 26 weeks of pregnancy to remain abstinent postpartum, taking puffs off a cigarette late in the pregnancy, and having two or more friends who smoked. The confidence and smoking lapse variables are consistent with predictors of relapse during pregnancy; however, the smoking environment variables, which appear to be contributors to postpartum relapse, were not associated with prepartum return to smoking in spontaneous quitters. This distinction suggests that whatever smoking environment constraints are operating while the woman is pregnant may be relaxed after delivery, possibly exposing her to a powerful cue to return to smoking. Further examination of changes in the smoking environment from prepartum to postpartum is warranted. It would be particularly helpful to determine whether the amount of smoking in the woman s presence increases after she is no longer pregnant. For a more general discussion of the factors that may account for postpartum relapse, see the article by Mullen in this issue. Intervention studies to prevent relapse among spontaneous quitters during pregnancy Although numerous randomized trials have tested smoking cessation interventions with pregnant smokers, relatively few studies have evaluated relapse prevention strategies with spontaneous quitters. Nine controlled outcome studies (and one uncontrolled pilot study) have examined several different approaches to the maintenance of abstinence during pregnancy. Some of these studies included both pregnant smokers and spontaneous quitters in their sample; however, investigators analyzed the end-ofpregnancy results separately, permitting outcomes to be examined for spontaneous quitters alone. The studies are not equal in their methodological rigor. Although most of the studies randomized participants to conditions, two relied on historical controls or partly randomized experimental designs. Some studies adhered to an intention-to-treat protocol and included participants lost to follow-up as smokers; however, many of the studies excluded from their analyses participants lost to follow-up. Two studies confirmed abstinence biochemically at baseline, but none of the studies restricted their analyses to baseline-verified spontaneous quitters. Most studies confirmed end-of-pregnancy abstinence biochemically, although some relied solely on selfreport. Finally, the studies differed greatly in their power to detect significant intervention effects. These methodological variations can influence outcomes, as can differences in the demographic characteristics of the study samples. With so few trials in the published literature, these variations make it difficult to draw conclusions. We organize our discussion of the studies around the type of intervention tested and conclude with a few observations about the findings. Table 3 summarizes these intervention trials. Three studies examined the impact of mailed relapse prevention self-help materials to spontaneous quitters receiving care through health maintenance organizations (HMOs) (Aaronson et al., 1985; Ershoff et al., 1995; Petersen et al., 1992). Aaronson and colleagues observed promising results in their small pilot study in which spontaneous quitters received eight self-help booklets (seven through the mail) over a 2-month period. Nearly 80% of participants reported reading most of the printed material. Urinary thiocyanate levels confirmed abstinence in the third trimester in 82% of the women, suggesting that the mailed selfhelp intervention may have been associated with high maintenance of abstinence during pregnancy. Unfortunately, two subsequent controlled trials testing the impact of mailed self-help materials failed to observe significant effects among privately insured spontaneous quitters. Petersen and colleagues (1992) found a 65% cotinine-confirmed abstinence rate among spontaneous quitters near the end of pregnancy, with no differences among usual care and mailed self-help experimental conditions. Ershoff et al. (1995) randomized spontaneous quitters to receive either a brief pamphlet and tip sheet on relapse prevention (control condition) or the same material plus eight booklets (four delivered at once in person, and four delivered weekly through the mail) to increase motivation for abstinence and to teach strategies for relapse prevention. Cotinine-confirmed abstinence rates near the end of pregnancy revealed no difference between conditions, with 84% of experimental participants and 80% of control participants demonstrating abstinence. Mailed self-help interventions do not appear to enhance maintenance of abstinence among privately insured spontaneous quitters, suggesting that other intervention delivery strategies may be necessary. McBride and colleagues (1999) added three monthly,

10 Table 3. Relapse prevention intervention studies with pregnant spontaneous quitters. Reference Design Sample size Intervention Measurement of smoking status % Quit near end of pregnancy Experimental Control Aaronson et al.,1985 Uncontrolled pilot study 23 Eight serially mailed self-help booklets, taped phone messages Ershoff et al., 1995 Experimental 171 Pamphlet and eight serially mailed self-help booklets Hajek et al., 2001 Experimental 249 Midwife-delivered relapse prevention advice, carbon monoxide feedback, buddy support Lowe et al., 1997 Experimental minute counseling, relapse prevention materials, social support enhancement, reinforcement from staff McBride et al., 1999 Experimental 395 Mailed self-help booklet, personalized letter, Petersen et al., 1992 Quasi-experimental, partly randomized three10-minute counseling calls 104 Mailed self-help manual and audiotape, reinforcement from providers in person and by mail Secker-Walker et al., 1995 Experimental 165 Nurse counseling at four prenatal visits, self-help materials Secker-Walker et al., 1998 Experimental 116 Obstetrician /midwife advice and nurse counseling at five prenatal visits, self-help materials Sexton & Hebel, 1984; Sexton et al.,1987 Valanis et al., 2001 Experimental 86 One or more home visits, monthly calls, biweekly mailings Quasi-experimental, historical control w1,000 Staff-delivered motivational interviewing and stage-of-change relapse prevention Self-report Urinary thiocyanate 100% 82% NA NA Urinary cotinine 84% 80% a Self-report and carbon monoxide at 10 days postpartum 65% 53% a,b,c Salivary thiocyanate 71% 56% d Self-report 87% 80% b,d Self-report Urinary cotinine Self-report Urinary cotinine/creatinine Self-report and CO Urinary cotinine 87% 65% 91% 70% 77% 68% 87% e 65% e 83% e 72% e 77% e 81% e Salivary thiocyanate 84% 75% e Self-report at 1 year, retrospective recall 73% 73% S212 SPONTANEOUS QUITTING Note. NA~not applicable. a Excludes those who moved away and miscarried but includes others who didn t respond to follow-up as smokers. b Significant difference between conditions. c Outcomes were assessed at 10 days postpartum and could have included postpartum relapse. d Includes losses to follow-up as smokers. e Excludes losses to follow-up.

11 NICOTINE & TOBACCO RESEARCH S minute telephone counseling calls to the provision of mailed self-help materials. Participants were spontaneous quitters enrolled from two large HMOs. At 28 weeks of pregnancy, 87% of spontaneous quitters randomized to receive the self-help materials plus telephone counseling reported abstinence, compared with 80% of spontaneous quitters randomized to receive self-help materials alone. This difference was significant; however, the absolute abstinence rates are probably inflated due to exclusive reliance on self-report. Unlike the prior studies, this study was adequately powered to test the effect, and the effect appeared to be due to the added impact of the three proactive telephone counseling calls. This finding suggests that more interactive interventions may hold promise for relapse prevention during pregnancy. Six studies explored the impact of face-to-face relapse prevention counseling alone or in conjunction with other cognitive intervention components on maintenance of abstinence among spontaneous quitters. Five of the studies observed no significant effect for additional health provider counseling during routine prenatal care appointments (Lowe et al., 1997; Secker-Walker et al., 1995, 1998; Valanis et al., 2001) or during special home visits (Sexton et al., 1984, 1987). These studies were conducted with both publicly and privately insured spontaneous quitters, and most reported good fidelity to the interventions. Only one study, conducted in England, observed an effect for a brief midwife-delivered counseling intervention. Hajek and colleagues (2001) enrolled 249 spontaneous quitters into either midwife-delivered usual care or up to 10 minutes of relapse prevention advice by a midwife including carbon monoxide feedback, written material on relapse prevention, and the offer to be paired with another pregnant smoker for mutual support. Point-prevalence abstinence assessed within 10 days after delivery and confirmed by a carbon monoxide level of less than 10 parts per million revealed a significant effect for the intervention, with 65% of the intervention condition spontaneous quitters abstinent, compared with 53% of spontaneous quitters in usual care. However, the difference was not observed when the dependent measure was continuous abstinence during pregnancy until 10 days postdelivery. The relatively low abstinence rates likely reflect the timing of the assessment, which was in the postpartum period rather than at the end of pregnancy. The authors noted that the buddy support was not routinely offered by the midwives in the intervention condition; therefore, the effect is attributed to the midwife advice, carbon monoxide feedback, and relapse prevention written material. The fact that this intervention was similar to those delivered in the other studies testing brief face-to-face relapse prevention counseling suggests that the absence of an effect in some of the earlier studies may have been due to inadequate power to detect a difference between conditions. Careful examination of these intervention trials reveals several patterns. First, most of the intervention studies were not sufficiently powered to find an effect. Data from across the studies suggest that about 70% of minimal intervention (control condition) spontaneous quitters are confirmed abstinent at the end of pregnancy. If we expect an experimental intervention to achieve a relative effect size of about 20% (85% abstinent in the intervention condition), then for a two-tailed test with 75% power, about 130 participants per condition would be needed. Only the studies by McBride et al. (1999), Hajek et al. (2001), and Valanis et al. (2001) were adequately powered to detect this level of difference. Not surprising, two of these three were the only studies to observe a significant effect for their intervention. Second, few studies confirmed abstinence in spontaneous quitters at baseline. In the two studies that did collect baseline urinary cotinine levels (Secker-Walker et al., 1995, 1998), 17% 21% of the spontaneous quitters showed evidence of smoking at baseline. The end-of-pregnancy abstinence rate among the confirmed spontaneous quitters (82%) was double the end-of-pregnancy abstinence rate among the women who were false negative at baseline (42%) (Secker-Walker et al., 1998). This finding suggests that many of the relapses observed in the relapse prevention trials may have been among women who were not abstinent to begin with. The inclusion of these women in the trials distorts our evaluation of relapse prevention interventions with true spontaneous quitters. Third, from some of the studies that published both self-reported and cotinine- or thiocyanate-confirmed abstinence rates at the end of pregnancy, it appears that self-reported, end-of-pregnancy abstinence may be inflated by as much as 20% 25% in both experimental and comparison conditions (Aaronson et al., 1985; Peterson et al., 1992; Secker-Walker et al., 1995). Carbon monoxide confirmation appears to reduce the inflation factor (Secker-Walker et al., 1998). Therefore, relapse prevention trials with pregnant spontaneous quitters should include biochemical confirmation of abstinence at the end of pregnancy. Finally, the interventions tested to date are largely variations on ways to deliver cognitive relapse prevention counseling (i.e., through self-help materials delivered in person or through the mail; through brief one-to-one counseling delivered in person or over the telephone). Other delivery channels for this intervention approach could be tested (e.g., Internet-based programs), but their impact likely will come more from expanded reach than from increased efficacy. To pursue enhanced efficacy, other intervention strategies should be examined with spontaneous quitters,

12 S214 SPONTANEOUS QUITTING including contingency-management systems that provide rewards for sustaining abstinence throughout pregnancy and postpartum, as in the smoking cessation study by Donatelle, Prows, Champeau, and Hudson (2000). Alternatively, because about 20% of women who report abstinence at baseline are still smoking and because some spontaneous quitters relapse fairly soon after quitting (V. P. Quinn, personal communication, July 22, 2002), perhaps more intensive counseling should occur early in the pregnancy between the first two prenatal visits. This approach might help ensure that abstinence is more firmly established and may lead to better end-ofpregnancy outcomes. Conclusions Spontaneous quitters represent 11% 28% of publicly insured pregnant smokers (Kendrick et al., 1995; Ockene et al., 2002; Secker-Walker et al., 1998; Windsor et al., 1985) and 40% 65% of privately insured pregnant smokers (Aaronson et al., 1985; Ershoff et al., 1995, 1999; McBride et al., 1999; Petersen et al., 1992; Saks et al., 2001). They differ from their continuing smoker counterparts in a number of ways. Compared with continuing smokers, spontaneous quitters are more likely to have higher education and income, be married or have a partner, have a planned pregnancy, be pregnant with their first child, enter prenatal care early, experience nausea or sickness during the first trimester, and intend to breast feed. They also are more likely to have a smoking history characterized by lower addiction to nicotine, have fewer smokers in their social environment, and believe more strongly that smoking can harm the developing fetus. From a public health perspective, spontaneous quitters stand out in their unique ability to remain abstinent for months after a quit date. Biochemically confirmed abstinence rates indicate that 65% 81% of spontaneous quitters maintain abstinence for up to 6 months during pregnancy. This finding contrasts sharply with the 0% 17% end-of-pregnancy abstinence rates observed in pregnant smokers who do not quit on their own prior to receiving prenatal care (Mullen, 1999; Windsor et al., 1998). Based on their representation in the population of pregnant smokers, spontaneous quitters make up the majority of pregnant smokers who quit smoking successfully during pregnancy. How spontaneous quitters manage to be so successful during pregnancy is not apparent from the research literature. Compared with spontaneous quitters who relapse, those who remain abstinent tend to be older, better educated, and having their first child; further, those who remain abstinent believe more strongly that smoking can harm the fetus and are more confident and motivated to stay quit. Additionally, they have had more days of abstinence when they appear for prenatal care. Efforts to enhance the ability of spontaneous quitters to remain abstinent through cognitive relapse prevention strategies have had limited impact. Methodological considerations, especially inadequate sample sizes in many of the intervention trials, may account for some of the failure to demonstrate treatment efficacy. However, minimal interventions, such as brief advice or tip sheets, may be about as good as more intensive interventions in sustaining abstinence in this population. Conversely, perhaps treatment strategies used to date have been too limited in scope, and other intervention approaches such as contingency management or more intensive counseling early in pregnancy should be tested. By quitting smoking early in their pregnancy, spontaneous quitters reduce the harm to the developing fetus caused by smoking; however, in most cases, their own lifelong health is compromised by their relapse to smoking postpartum. Over 60% of spontaneous quitters return to smoking by 6 months after delivery. This pattern of relapse after a smoke-free pregnancy is similar to the temporary abstinence from alcohol observed in many pregnant women. Unfortunately, resumption of cigarette smoking is associated with more serious long-term health consequences than is resumption of moderate drinking. For this reason, and because smoking has adverse health consequences for children exposed to secondhand smoke, resumption of smoking postpartum is worthy of attention. Few studies have identified or prioritized the range of factors that may be contributing to postpartum relapse in spontaneous quitters, but what little evidence exists suggests that the smoking environment may play an important role. What we know about spontaneous quitters is overshadowed by what we don t know. For example, we don t know whether the proportion of spontaneous quitters among pregnant smokers has changed over time. National data have not tracked smoking by trimester of pregnancy, precluding the opportunity to observe changes in the proportions of prepregnancy smokers who quit smoking during the first trimester of their pregnancy (a rough estimate of spontaneous quitting). Fortunately, the 2003 revision of the U.S. Standard Certificate of Live Birth will include documentation on smoking immediately before pregnancy and by trimester of pregnancy. This revision will set in place a national monitoring system for tracking changes over time. We don t know much about the influence of pregnancy-specific physiological and endocrinological changes on smoking behavior. For example, it is unclear how hormonal changes during pregnancy affect temptations to smoke or the experience of withdrawal symptoms. Although research indicates that