Olfactory and gustatory sensory changes to tobacco smoke in pregnant smokers

Gustatory and olfactory shifts during pregnancy and the postpartum period: A systematic review and meta-analysis

Pregnancy is a transformative phase marked by significant behavioral and physiological changes. Substantial changes in pregnancy-related hormones are thought to induce changes in chemosensory perception, as often observed in non-human animals. However, empirical behavioral research on pregnancy-related olfactory or gustatory changes has not yet reached a consensus. This PROSPERO pre-registered systematic review and meta-analysis evaluated published data of olfactory and gustatory changes in pregnant individuals, across the three pregnancy trimesters and postpartum period. Our comprehensive search strategy identified 20 relevant studies, for inclusion in the meta-analysis. The meta-analysis revealed that pregnant individuals, regardless of trimester, performed significantly poorer in terms of odour identification, however, no difference was detected between non-pregnant controls and women postpartum. Additionally, pregnant women in the second and third trimester rated olfactory stimuli to be more intense. A slight decline in odour pleasantness ratings was observed amongst those in the second trimester. No major difference was observed between pregnant and non-pregnant subjects in terms of gustatory functions, except the first trimester appeared to be associated with increased pleasantness for the sweet taste. Post-hoc meta-regression analyses revealed that pregnancy stage was a significant predictor for observed effect size for odour intensity ratings, but not for odour identification scores. These findings provide valuable insights into the interplay between pregnancy and chemosensory perception, highlighting systematic physiological changes due to pregnancy. Healthcare providers can also utilize the knowledge of sensory shifts to better support pregnant women in making appropriate dietary choices, managing sense-related discomfort, and leading to potential sensory interventions. Overall, this research enhances our comprehension of sensory shifts during pregnancy, benefiting maternal health and pregnancy-related care.

Within-person decline in pregnancy smoking is observable prior to pregnancy awareness: Evidence across two independent observational cohorts

Decreased consumption of nicotine and other drugs during pregnancy appears to be a cross-species phenomenon from which mechanism(s) capable of interrupting addictive processes could be elucidated. Whether pregnancy influences smoking behaviour independent of women's knowledge of the pregnancy, however, has not been considered. Using repeated measures analysis of variance (ANOVA), we estimated within-person change in mean cigarettes/day smoked across the estimated date of conception but prior to individually reported dates of pregnancy recognition using longitudinal smoking data from two independent observational cohorts, the Growing Up Healthy (GUH, n = 271) and Midwest Infant Development Studies (MIDS, n = 145). Participants smoked an average of half a pack/day in the month immediately before conception (M (SD) = 12(8.1) and 9.5(6.7) cigarettes/day in GUH and MIDS, respectively). We observed within-person declines in smoking after conception, both before (MGUH  = -0.9; 95% CI -1.6, -0.2; p = 0.01; MMIDS  = -1.1; 95% CI -1.9, -0.3; p = 0.01) and after (MGUH  = -4.8; 95% CI -5.5, -4.1; p < 0.001; MMIDS  = -3.3; 95% CI -4.4, -2.5; p < 0.001) women were aware of having conceived, even when women who had quit and women who were planning to conceive were excluded from analyses. Pregnancy may interrupt smoking-related processes via mechanisms not previously considered. Plausible candidates and directions for future research are discussed.

The low prevalence of female smoking in the developing world: gender inequality or maternal adaptations for fetal protection?

BACKGROUND

Female smoking prevalence is dramatically lower in developing countries (3.1%) than developed countries (17.2%), whereas male smoking is similar (32% vs 30.1%). Low female smoking has been linked to high gender inequality. Alternatively, to protect their offspring from teratogenic substances, pregnant and lactating women appear to have evolved aversions to toxic plant substances like nicotine, which are reinforced by cultural proscriptions. Higher total fertility rates (TFRs) in developing countries could therefore explain their lower prevalence of female smoking.

OBJECTIVE

To compare the associations of TFR and gender inequality with national prevalence rates of female and male smoking.

METHODS

Data from a previous study of smoking prevalence vs gender inequality in 74 countries were reanalysed with a regression model that also included TFR. We replicated this analysis with three additional measures of gender equality and 2012 smoking data from 173 countries.

RESULTS

A 1 SD increase in TFR predicted a decrease in female smoking prevalence by factors of 0.58-0.77, adjusting for covariates. TFR had a smaller and unexpected negative association with male smoking prevalence. Increased gender equality was associated with increased female smoking prevalence, and, unexpectedly, with decreased male smoking prevalence. TFR was also associated with an increase in smoking prevalence among postmenopausal women.

CONCLUSIONS

High TFR and gender inequality both predict reduced prevalence of female smoking across nations. In countries with high TFR, adaptations and cultural norms that protect fetuses from plant toxins might suppress smoking among frequently pregnant and lactating women.

Postpartum smoking relapse--a thematic synthesis of qualitative studies

BACKGROUND AND AIMS

Many women quit smoking during pregnancy, but relapse after the baby is born. To understand why and identify ways of preventing this, this study reviewed the qualitative literature on women's experience of postpartum smoking relapse.

METHODS

A systematic review of qualitative studies and process evaluations of trials. We undertook a thematic synthesis of published qualitative data.

RESULTS

We screened 1336 papers. Twenty-two papers reporting on 16 studies were included, reporting on the views of 1031 postpartum women. Factors affecting relapse and barriers and facilitators to relapse prevention were identified around the key themes of beliefs, social influences, motivation, physiological factors and identity. Women's beliefs about smoking as a means of coping with stress and the need for social support, especially from a partner, emerged as important. Extrinsic motivation to quit during the pregnancy (for the health of the fetus) appeared to be a factor in prompting relapse after the baby was born. During the immediate postpartum period women believed that physiological changes influence cigarette cravings. The stress of caring for a newborn, sleeplessness and adjusting to a new mothering identity were also reported to be important.

CONCLUSIONS

Among women who quit smoking during pregnancy, those who relapse postpartum talk commonly about no longer needing to protect the baby and the effects of stress. Partner support and a sense of changed identity are cited as factors preventing relapse.

The effects of smoked nicotine on measures of subjective states and hypothalamic-pituitary-adrenal axis hormones in women during the follicular and luteal phases of the menstrual cycle

OBJECTIVES

To determine the acute effects of cigarette smoking on hypothalamic-pituitary-adrenal (HPA) axis hormones and subjective states as a function of the menstrual cycle in nicotine-dependent women.

METHODS

Seventeen healthy nicotine-dependent women were studied during the follicular and/or luteal phase of the menstrual cycle. Because of observation of a possible bimodal distribution of progesterone levels within the luteal phase group, we performed a set of a posteriori analyses. Therefore, we divided the luteal group into a low progesterone and a high progesterone groups.

RESULTS

Smoked nicotine activated HPA, measured by adrenocorticotropin hormone (ACTH), cortisol, and dehydroepiandrosterone (DHEA) response and affected subjective states in both follicular and luteal phases, with increased "High," "Rush," and decreased "Craving." The HPA stimulation revealed a blunting of ACTH response. There was only modest evidence for a blunting of subjective state responses in the luteal phase. However, upon post hoc analyses, the high progesterone luteal group showed a marked blunting of measures of subjective states and a blunted ACTH response. Examining the association between hormone and measures of subjective states revealed tentative associations of ACTH stimulation with increased "Rush" and "Craving," and DHEA stimulation with increased "Craving."

CONCLUSIONS

This pilot study suggests that menstrual cycle phase differences in progesterone levels may attenuate nicotine's addictive effects via diminution of its reinforcing properties and augmentation of its aversive effects interfering with the pleasure associated with cigarette smoking.

Smoking cessation, maintenance, and relapse experiences among pregnant and postpartum adolescents: a qualitative analysis

PURPOSE

To understand the experiences and processes of smoking cessation, maintenance, and relapse for pregnant and postpartum adolescents, whose perspectives and needs might be different from other age groups.

METHODS

We conducted in-depth semistructured interviews with 52 pregnant and postpartum adolescents using tools of grounded theory analysis.

RESULTS

Spontaneous smoking cessation during pregnancy was reported by most participants. This was generally explained as resulting from knowledge about the harmful effects of tobacco on the fetus, intense emotional reactions to this knowledge, or unpleasant tobacco- and pregnancy-related physical symptoms. Relapses were common, however. Most participants experienced guilt when they relapsed during pregnancy. Postpartum relapse was less fraught, as many participants no longer considered their smoking to negatively affect their infants. This was found even among adolescents who were breastfeeding. Participants who did maintain cessation postpartum typically reported support from smoke-free families and environments.

CONCLUSIONS

The results of this study suggest a constellation of protective factors that contribute to smoking cessation and maintenance during and after pregnancy, as well as risk factors that contribute to temporary or permanent relapses. These results can inform future research and interventions on tobacco prevention among pregnant and postpartum adolescents. Several promising strategies for intervention development are discussed.

Explaining human recreational use of 'pesticides': The neurotoxin regulation model of substance use vs. the hijack model and implications for age and sex differences in drug consumption

Most globally popular drugs are plant neurotoxins or their close chemical analogs. These compounds evolved to deter, not reward or reinforce, consumption. Moreover, they reliably activate virtually all toxin defense mechanisms, and are thus correctly identified by human neurophysiology as toxins. Acute drug toxicity must therefore play a more central role in drug use theory. We accordingly challenge the popular idea that the rewarding and reinforcing properties of drugs "hijack" the brain, and propose instead that the brain evolved to carefully regulate neurotoxin consumption to minimize fitness costs and maximize fitness benefits. This perspective provides a compelling explanation for the dramatic changes in substance use that occur during the transition from childhood to adulthood, and for pervasive sex differences in substance use: because nicotine and many other plant neurotoxins are teratogenic, children, and to a lesser extent women of childbearing age, evolved to avoid ingesting them. However, during the course of human evolution many adolescents and adults reaped net benefits from regulated intake of plant neurotoxins.

Sequential screening for psychosocial and behavioural risk during pregnancy in a population of urban African Americans

OBJECTIVE

Screening for psychosocial and behavioural risks, such as depression, intimate partner violence, and smoking, during pregnancy is considered to be state of the art in prenatal care. This prospective longitudinal analysis examines the added benefit of repeated screening, compared with a single screening, in identifying such risks during pregnancy.

DESIGN

Data were collected as part of a randomised controlled trial to address intimate partner violence, depression, smoking, and environmental tobacco smoke exposure in African American women.

SETTING

Prenatal care sites in the District of Columbia serving mainly women of minority background.

POPULATION

A cohort of 1044 African American pregnant women in the District of Columbia.

METHODS

Mothers were classified by their initial response (acknowledgement of risks), and these data were updated during pregnancy. Risks were considered new if they were not previously reported. Standard hypothesis tests and logistic regression were used to predict the acknowledgment of any new risk(s) during pregnancy.

MAIN OUTCOME MEASURES

New risks: psychosocial variables to understand what factors might help identify the acknowledgement of additional risk(s).

RESULTS

Repeated screening identified more mothers acknowledging risk over time. Reported smoking increased by 11%, environmental tobacco smoke exposure increased by 19%, intimate partner violence increased by 9%, and depression increased by 20%. The psychosocial variables collected at the baseline that were entered into the logistic regression model included relationship status, education, Medicaid, illicit drug use, and alcohol use during pregnancy. Among these, only education less than high school was associated with the acknowledgement of new risk in the bivariate analyses, and significantly predicted the identification of new risks (OR 1.39, 95% CI 1.01-1.90).

CONCLUSIONS

It is difficult to predict early on who will acknowledge new risks over the course of pregnancy, and thus all women should be screened repeatedly to allow for the identification of risks and intervention during prenatal care.

Smoking cessation and relapse among pregnant African-American smokers in Washington, DC

Smoking is the single most preventable cause of perinatal morbidity. This study examines smoking behaviors during pregnancy in a high risk population of African Americans. The study also examines risk factors associated with smoking behaviors and cessation in response to a cognitive behavioral therapy (CBT) intervention. This study is a secondary analysis of data from a randomized controlled trial addressing multiple risks during pregnancy. Five hundred African-American Washington, DC residents who reported smoking in the 6 months preceding pregnancy were randomized to a CBT intervention. Psycho-social and behavioral data were collected. Self-reported smoking and salivary cotinine levels were measured prenatally and postpartum to assess changes in smoking behavior. Comparisons were made between active smokers and those abstaining at baseline and follow-up in pregnancy and postpartum. Sixty percent of participants reported quitting spontaneously during pregnancy. In regression models, smoking at baseline was associated with older age, <a high school education and illicit drug use. At follow-up closest to delivery, smoking was associated with lower education, smoking and cotinine level at baseline and depression. At postpartum, there was a relapse of 34%. Smokers postpartum were significantly more likely to smoke at baseline and use illicit drugs in pregnancy. Mothers in the CBT intervention were less likely to relapse. African-American women had a high spontaneous quit rate and no response to a CBT intervention during pregnancy. Postpartum mothers' resolve to maintain a quit status seems to wane despite their prolonged period of cessation. CBT reduced postpartum relapse rates.

Development and validation of the smoking cue appeal survey

In this two-study investigation, a measure of sensory smoking cue appeal was developed and evaluated relative to smoking behavior, smoking severity, and craving. In the first study, 101 participants completed the Smoking Cue Appeal Survey (SCAS) and self-reported smoking status (current, former, or non-smoker). In the second study, 54 participants completed the SCAS and craving was measured following a cue exposure procedure. Data were collected between 2008 and 2009. The SCAS demonstrated good psychometric properties and was associated with smoking status. Additionally, craving was significantly associated with the SCAS, but there was no association with frequency of smoking or severity of nicotine dependence. Limitations include a cross-sectional design, small sample size, and focus on trait factors. Future directions are discussed.