Perinatal complications associated with maternal tobacco use

Substance use during pregnancy: time for policy to catch up with research

The phenomenon of substance abuse during pregnancy has fostered much controversy, specifically regarding treatment vs. punishment. Should the pregnant mother who engages in substance abuse be viewed as a criminal or as someone suffering from an illness requiring appropriate treatment? As it happens, there is a noticeably wide range of responses to this matter in the various states of the United States, ranging from a strictly criminal perspective to one that does emphasize the importance of the mother's treatment. This diversity of dramatically different responses illustrates the failure to establish a uniform policy for the management of this phenomenon. Just as there is lack of consensus among those who favor punishment, the same lack of consensus characterizes those states espousing treatment. Several general policy recommendations are offered here addressing the critical issues. It is hoped that by focusing on these fundamental issues and ultimately detailing statistics, policymakers throughout the United States will consider the course of action that views both pregnant mother and fetus/child as humanely as possible.

The complex relationship between smoking in pregnancy and very preterm delivery. Results of the Epipage study

OBJECTIVE

To assess the relationship between cigarette smoking during pregnancy and very preterm births, according to the main mechanisms of preterm birth.

DESIGN

Case-control study (the French Epipage study).

SETTING

Regionally defined population of births in France.

POPULATION

Eight hundred and sixty-four very preterm live-born singletons (between 27 and 32 completed weeks of gestation) and 567 unmatched full-term controls.

METHODS

Data from the French Epipage study were analysed using a polytomous logistic regression model to control for social and demographic characteristics, pre-pregnancy body mass index and obstetric history. The main mechanisms of preterm delivery were classified as gestational hypertension, antepartum haemorrhage, premature rupture of membranes, spontaneous preterm labour and other miscellaneous mechanisms.

MAIN OUTCOME MEASURES

Odds ratios for very preterm birth for low to moderate (1-9 cigarettes/day) and heavy (>/=10 cigarettes/day) maternal smoking in pregnancy, estimated according to the main mechanisms leading to preterm birth.

RESULTS

Smokers were more likely to give birth to very preterm infants than non-smokers [adjusted odds ratio (aOR) 1.7, 95% confidence interval (CI) 1.3-2.2]. Heavy smoking significantly reduced the risk of very preterm birth due to gestational hypertension (aOR 0.5, 95% CI 0.3-1.0), whereas both low to moderate and heavy smoking increased the risk of very preterm birth due to all other mechanisms (aOR between 1.6 and 2.8).

CONCLUSION

These data from the Epipage study show that maternal smoking during pregnancy is a risk factor for very preterm birth. The impact of maternal smoking on very preterm birth appears to be complex: it lowers the risk of very preterm birth due to gestational hypertension, but increases the risk of very preterm birth due to other mechanisms. These findings might explain why maternal smoking is more closely related to preterm birth among multiparous women than among nulliparous women.

Preconceptional health promotion: progress in changing a prevention paradigm

Preconceptional health promotion is a proven strategy to impact reproductive outcomes. Despite energy to incorporate this prevention strategy into the care of women in this country, little evidence exists that the paradigm shift necessary to reframe the clinical care of women has occurred or that public awareness about critical opportunities for preventing reproductive casualties is high. This article reviews the rationale for preconceptional counseling, discusses progress in moving the agenda of prepregnancy wellness forward, and reveals some of the lessons learned from efforts to redesign prevention emphases for reproductive healthcare.

Birth characteristics and hepatoblastoma risk in young children

BACKGROUND

Although hepatoblastoma is a very rare childhood cancer, its incidence appears to be rising, especially among children with very low birth weight. With the exception of documented correlations with certain congenital anomalies, the etiology of hepatoblastoma remains largely unknown.

METHODS

Using California's population-based cancer registry, the authors identified 113 children ages birth-4 years with hepatoblastoma who were diagnosed between 1988 and 1997. Ninety-nine of those 113 children (88%) were matched to a California birth certificate, and randomly selected controls from the same birth certificate files were matched to cases (4:1) according to the month and year of birth and gender. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using conditional logistic regression analyses.

RESULTS

A strikingly elevated risk of hepatoblastoma was found in children who were born with very low birth weight (< 1500 g; OR, 50.57; 95% CI, 6.59-387.97). A plot of the distribution by birth weight showed interesting peaks at birth weights < 1000 g and 3000-3499 g among cases. Children who weighed < 1000 g showed a statistically significant, linear trend toward being diagnosed at an older age (P = 0.036), which seemed to be explained in part by gestational age.

CONCLUSIONS

The results confirmed previously reported findings of an increased hepatoblastoma risk among children with very low birth weight and suggested that the etiology may differ between children with very low birth weight and children with normal birth weight.

Genetics and drug use as a complex phenotype

Drug use is a complex behavior influenced by multiple biological, family, and sociocultural factors. The concurrent use/misuse of multiple drugs is often seen and drug use also co-occurs with other psychiatric conditions. Behavior and molecular genetic studies support an important posited role of genes in drug use. This posited genetic risk does not appear to be conferred by one or two major genes manifesting large effects, but rather by a number of genes manifesting smaller effects. Genetic factors explain, on average, only about half of the total variability in drug use, with the remaining variability influenced by environmental factors. Also, genetic risk may be differentially expressed in the presence vs. absence of particular environmental conditions. Thus, investigation of environmental factors and their interaction with genetic risk is a necessary component of genetic research. While the full potential of genetic investigations for the prevention of drug misuse has yet to be realized, an example of the impact of risk factor modification under various conditions of gene-environment interaction is provided, and the implications for use of genetic information in drug-misuse prevention are discussed. The multifactorial nature of drug use necessitates coordinated investigation from multiple disciplines and timely dissemination of scientific findings. In addition, this work demands adherence to the highest standards of confidentiality and ethical use of genetic information to best inform future prevention efforts.

Adverse health effects of prenatal and postnatal tobacco smoke exposure on children

Parents who choose to smoke are possibly not aware of, or deny, the negative effects of passive smoking on their offspring. This review summarises a wide range of effects of passive smoking on mortality and morbidity in children. It offers paediatricians, obstetricians, specialists in preventive child health care, general practitioners, and midwives an approach to promote smoking cessation in smoking parents before, during, and after pregnancy.

Context and beliefs about smoking and smoking cessation

PURPOSE

To describe the context of, and beliefs about, smoking cessation in a sample of low-income African American pregnant women.

STUDY DESIGN & METHODS

A naturalistic descriptive qualitative approach was used with 15 women. Face-to-face interviews were conducted using a semi-structured interview guide. Interviews were transcribed verbatim and a thematic content analysis conducted. Perinatal health complication data were extracted from the participants' medical records and summarized.

RESULTS

Two major themes were identified. The context of smoking cessation theme was Living the Stressful Life, with subthemes of Personal and Community Stress, Personal Health Problems, and Smoking For Stress Management. The second major theme was Personal Accountability for Smoking Cessation. There was a mismatch between women's sources of stress (which were out of their control) and their perceived locus of change (which was personal behavior).

CLINICAL IMPLICATIONS

To improve the outcomes of tobacco control programs for low-income women, we need to take action to create healthier communities.

Adverse pregnancy outcomes in snuff users

OBJECTIVE

The purpose of the study was to evaluate the effects of smokeless tobacco use during pregnancy.

STUDY DESIGN

We examined birth weight, preterm delivery, and preeclampsia in women who were delivered of singleton, live-born infants in Sweden from 1999 through 2000. For each snuff user, 10 cigarette smokers and 10 tobacco nonusers were selected randomly.

RESULTS

After exclusions, 789 snuff users, 11,240 smokers, and 11,495 nonusers remained. Compared with nonusers, adjusted mean birth weight was reduced in snuff users by 39 g (95% CI, 6-72 g) and in smokers by 190 g (95% CI, 178-202 g). Preterm delivery was increased in snuff users and smokers (adjusted odds ratios, 1.98 [95% CI, 1.46-2.68] and 1.57 [95% CI, 1.38-1.80], respectively). Preeclampsia was reduced in smokers (adjusted odds ratio, 0.63; 95% CI, 0.53-0.75) but increased in snuff users (adjusted odds ratio, 1.58; 95% CI, 1.09-2.27).

CONCLUSION

Snuff use was associated with increased risk of preterm delivery and preeclampsia. Snuff does not appear to be a safe alternative to cigarettes during pregnancy.

Maternal asthma is associated with reduced female fetal growth

Asthma during pregnancy is associated with a low birth weight, although the mechanisms contributing to this outcome remain unknown. The relationship between maternal asthma and its treatment, placental function, fetal sex, and low birth weight was examined to establish the effect of asthma on fetal growth. Glucocorticoid intake by women with asthma was assessed throughout pregnancy. The placenta was collected after delivery, and 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) activity was measured. Fetal cortisol and estriol were measured in the umbilical vein plasma at delivery. Those with asthma were compared with a nonasthmatic control group. In women with asthma who did not use inhaled steroids and were pregnant with a female fetus, we observed significantly reduced birth weights, whereas male birth weights were unaffected. The presence of a female fetus was associated with significantly increased maternal circulating monocytes, significantly reduced placental 11beta-HSD2 activity and fetal estriol, and a trend toward elevated fetal plasma cortisol. This study provides evidence that in pregnancies complicated by asthma there is a fetal sex-specific effect on the maternal immune system with adverse effects on placental function and female fetal growth.

Preterm birth among African American and white women: a multilevel analysis of socioeconomic characteristics and cigarette smoking

STUDY OBJECTIVE

Research shows that neighbourhood socioeconomic factors are associated with preterm delivery. This study examined whether cigarette smoking and individual socioeconomic factors modify the effects of neighbourhood factors on preterm delivery.

DESIGN

Case-control study.

SETTING

Moffit Hospital in San Francisco, California.

PARTICIPANTS

417 African American and 1244 white women, including all preterm and a random selection of term deliveries 1980-1990, excluding non-singleton pregnancies, congenital anomolies, induced deliveries, and women transported for special care. US census data from 1980 and 1990 were used to characterise the women's neighbourhoods, defined as census tracts.

RESULTS

Cigarette smoking increased the risk of preterm delivery among both African American (OR=1.77, 95% confidence intervals (CI) (1.12 to 2.79)) and white women (OR=1.25, 95% CI (1.01 to 1.55)). However, cigarette smoking did not attenuate or modify the association of neighbourhood factors with preterm delivery. Among African American women, having public insurance modified the relation between neighbourhood unemployment and preterm delivery; among women without public insurance, the risk of preterm delivery was low in areas with low unemployment and high in areas with high unemployment, while among women with public insurance the risk of preterm delivery was highest at low levels of neighbourhood unemployment.

CONCLUSIONS

Cigarette smoking was associated with preterm delivery, especially among African Americans. Adverse neighbourhood conditions had an influence on preterm delivery beyond that of cigarette smoking. The effects of some neighbourhood characteristics were different depending on individual socioeconomic status. Examining socioeconomic and behavioural/biological risk factors together may increase understanding of the complex causes of preterm delivery.

Smoking during pregnancy and newborn neurobehavior

OBJECTIVE

This was a prospective study of the effects of maternal smoking during pregnancy on newborn neurobehavior, including dose-response relationships using self-report and a bioassay of nicotine exposure.

METHODS

The sample included 27 nicotine exposed and 29 unexposed full-term newborn infants with no medical problems from comparable social class backgrounds. Mothers were excluded for using illegal drugs during pregnancy, using antidepressant medication, or if they consumed >3 alcoholic drinks per month. Nicotine exposure was determined by maternal self-report and cotinine in maternal saliva. The NICU Network Neurobehavioral Scale (NNNS) was administered by masked examiners in hospital to measure neurobehavioral function. NNNS scores were compared between nicotine-exposed and -unexposed groups including adjustment for covariates. Dose-response relationships with NNNS scores were computed for maternal salivary cotinine and maternal report of number of cigarettes per day during pregnancy.

RESULTS

After adjustment for covariates, the tobacco-exposed infants were more excitable and hypertonic, required more handling and showed more stress/abstinence signs, specifically in the central nervous system (CNS), gastrointestinal, and visual areas. Dose-response relationships showed higher maternal salivary cotinine values related to more stress/abstinence signs (r =.530) including CNS (r =.532) and visual stress (r =.688) and higher excitability scores (r =.617). Cigarettes per day during pregnancy was related to more stress/abstinence signs (r =.582) including CNS (r =.561) and visual stress (r =.640).

CONCLUSIONS

These findings suggest neurotoxic effects of prenatal tobacco exposure on newborn neurobehavior. Dose-response relationships could indicate neonatal withdrawal from nicotine. Research directed at understanding the effects of cigarette smoking during pregnancy on infants can lead to improved public health outcome.

Smoking enhances oxytocin-induced rhythmic myometrial contraction

Although smoking during pregnancy is one of the major risk factors of premature delivery, the underlying mechanism by which smoking causes premature delivery is unknown. In the present study, we examined the effects of smoking on uterine contractility induced by oxytocin and prostaglandin F(2alpha). Rats inhaled either cigarette smoke or room air from Day 14 to Day 16 of pregnancy through an inhalation apparatus for experimental animals (type "Hamburg II"). After the rats were killed on Day 17 of pregnancy, the uterine contractile sensitivity and activity on exposure to oxytocin or prostaglandin F2alpha were investigated. The expression levels of oxytocin-receptor mRNA and prostaglandin F(2alpha) receptor mRNA in the uterus were investigated by reverse transcription-polymerase chain reaction. The contractile activity was assessed as the contractile force and the frequency of rhythmic contractions of myometrial strips that were treated with oxytocin or prostaglandin F(2alpha). The contractile sensitivity to oxytocin was significantly higher in the smoking group than in the control group (P < 0.01). Although the contractile force of oxytocin-induced contractions did not differ between the smoking and control groups, the frequency of contractions was significantly higher in the smoking group than in the control group (P < 0.01). On the other hand, no significant differences were found in the contractile sensitivity and activity in response to prostaglandin F(2alpha) between the smoking and control groups. The expression of oxytocin-receptor mRNA in the myometrium was significantly increased in the smoking group compared with the control group (P < 0.01). However, no significant difference was found in the level of expression of prostaglandin F(2alpha)-receptor mRNA between the two groups. These results suggest that smoking during pregnancy increases the contractile sensitivity and activity of the myometrium in response to oxytocin by up-regulating the expression of oxytocin-receptor mRNA. The effects of smoking on the contractile sensitivity and activity of the myometrium in response to oxytocin may increase the risk of premature delivery in smokers.

The impact of smoking and other substance use by urban women on the birthweight of their infants

The impact of maternal smoking and other substance use during pregnancy on infant birthweight is demonstrated in a sample of 766 urban women, using data collected in the Washington, D.C. Metropolitan Area Drug Study (DC*MADS). Women residing and giving birth in the District of Columbia were interviewed in 1992. A multivariable linear regression model was used to quantify the association between birthweight and the mother's use of cigarettes, alcohol, or illicit drugs during pregnancy, while controlling for possible confounding variables. The analysis focused on factors, including prenatal care and substance use during pregnancy that may contribute to low birthweight infants born to this sample of urban, predominantly black women. A woman's use of cigarettes, marijuana, and heroin during pregnancy was related to infant birthweight, but her use of alcohol and cocaine during pregnancy was not significantly related. Smoking during pregnancy was a strong predictor for low birthweight, suggesting that targeting more smoking cessation programs for pregnant women, particularly those who may also be illicit drug users, could help reduce adverse health consequences for low birthweight infants.

Fetal tobacco syndrome and perinatal outcome

OBJECTIVE

The aim of this study was to evaluate perinatal outcome in newborns of mothers who are smokers.

METHODS

The study included 87 pregnant women with a single pregnancy in the cephalic position, 64 of them nonsmokers (group 1), 13 who smoked 5-20 cigarettes per day (group 2) and 10 who smoked more than 20 cigarettes per day (group 3). Maternal demographic variables and laboratory hemoglobin concentration, hematocrit and erythrocyte count in the last trimester were recorded. Perinatal outcome included type of delivery (vaginal or cesarean section), birth weight, occurrence of meconium in the amniotic fluid, 5-min Apgar score, umbilical arterial blood pH postpartum, sex of the newborn, need for treatment at a neonatal intensive care unit (NICU) and clinically and neurosonographically verified postpartum neurologic complications in the newborn.

RESULTS

A statistically significant correlation (p < 0.01) was found with the mean gestational age at delivery in all three groups of women, especially in those smoking >20 cigarettes per day, who had a higher incidence of premature deliveries. Maternal laboratory findings also differed significantly among the three groups of women, i.e. erythrocyte count (p < 0.01), hemoglobin concentration (p < 0.01) and hematocrit (p < 0.001). The rate of delivery by cesarean section was significantly higher in the groups of smokers, irrespective of the number of cigarettes per day (groups 2 and 3). Birth weight was lower by about 250 and 350 g (p < 0.001) in groups 2 and 3, respectively. Five-minute Apgar score and umbilical arterial blood pH were lower in group 3 as compared with groups 1 and 2 (p < 0.01). NICU treatment was required in more than 50% of infants born to group 3 mothers, in whom 70% of perinatal neurologic complications such as subependymal hemorrhage, periventricular hemorrhage, porencephalic cysts, intracranial hemorrhage and swallowing disturbance of the newborn were recorded (p < 0.001). The infants born to group 3 mothers had a longer and more difficult period of adaptation, thus often requiring an NICU stay.

CONCLUSION

Our study confirmed that pregnancy burdened with smoking, especially in the case of >20 cigarettes a day, is associated with a high risk due to the development of maternal anemia and fetal hypoxia and polyglobulia, which in turn result in a significantly poorer perinatal outcome in infants born to smoking mothers and compromised subsequent development of the child, as evidenced by the morphological substrates on the brain resulting from the fetal mechanism of defense against hypoxia. Clinically, there was no other (etiologic) reason for (chronic) fetal hypoxia; thus, the clinical substrate of fetal tobacco syndrome could be presumed to have developed consequentially to chronic smoking during pregnancy, as a preuterine factor of fetal hypoxia. Other gestational or gestation-related diseases (e.g., gestosis, diabetes) that may potentially cause nutritional and respiratory insufficiency of the placenta were ruled out.

Reduction of primary and secondary smoke exposure for low-income black pregnant women

Cigarette smoking by women during pregnancy continues to be a substantial contributor to poor perinatal outcomes in the United States. Decreasing tobacco smoke exposure for women and children is a lifestyle change that will improve perinatal health. A study was conducted with a sample of 74 low-income black women to evaluate the effectiveness of the Smoke Free Families intervention in moving pregnant women forward in the stages of change toward becoming a non-smoker and reducing exposure to second-hand smoke. Transtheoretical model variables were measured at intake, postintervention, and during the last month of pregnancy. There were no statistically significant differences between treatment and control group in movement forward in the stages of change. The findings raise questions about the conceptual fit of the transtheoretical model with pregnant women. We discuss additional interventions and suggest types of studies that would provide new insight into tobacco exposure issues for pregnant women.

Smoking before pregnancy and risk of gestational hypertension and preeclampsia

OBJECTIVE

Our purpose was to determine whether smoking before pregnancy reduces the risk of gestational hypertension or preeclampsia.

STUDY DESIGN

The trial of Calcium for Preeclampsia Prevention (CPEP) was a randomized study of 4589 nulliparous women conducted in 5 US medical centers during the years 1992 through 1995. Women were classified into 4 exposure groups by smoking history obtained at study enrollment (13-21 weeks' gestation): (1) never smoked, (2) smoked but quit before the last menstrual period (LMP), (3) smoked but quit after LMP but before enrollment, and (4) smoked and still smoking at enrollment.

RESULTS

After adjustments were made for maternal age, race, body mass index, type of health insurance, and clinical center, women smoking at enrollment had a reduced risk of hypertension (relative risk = 0.8; 95% CI, 0.6-0.9). Women who quit smoking before the LMP did not have reduced risk (relative risk = 1.1; 95% CI, 0.9-1.3). Results were similar for gestational hypertension and preeclampsia examined separately.

CONCLUSION

Women who smoke but quit before becoming pregnant do not have a reduced risk for gestational hypertension or preeclampsia.

Smoking in pregnancy

This update discusses the evidence to link maternal smoking during pregnancy with adverse pregnancy outcome, and also the potential long-term effects on health of in-utero exposure to tobacco smoke. Smoking cessation strategies will also be considered.

Reduced 11beta-hydroxysteroid dehydrogenase type 2 activity is associated with decreased birth weight centile in pregnancies complicated by asthma

Pregnancies complicated by asthma are associated with an increased risk of low birth weight. Currently, the mechanisms causing this outcome are unknown. To investigate whether impaired placental function may be a determinant, we measured placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) activity, protein and mRNA, placental CRH mRNA, fetal cortisol, and fetal estriol concentrations at delivery. Asthmatic subjects were classified according to inhaled glucocorticoid intake during pregnancy and compared with a control nonasthmatic group. There was a 25% reduction in neonatal birth weight centile in asthmatic women who did not use inhaled glucocorticoid treatment. This was accompanied by significantly reduced placental 11beta-HSD2 activity, significantly increased fetal cortisol, and a trend toward increased placental CRH mRNA and reduced fetal estriol concentrations. The use of inhaled glucocorticoids for treatment was associated with birth weight centile, 11beta-HSD2 activity, CRH mRNA, fetal cortisol, and estriol concentrations similar to control levels. There was a significant inverse correlation between fetal cortisol and fetal estriol concentrations across all groups. These studies demonstrate that inhaled glucocorticoid intake for the treatment of asthma is associated with improved placental function and fetal outcome, suggesting that inflammatory factors associated with asthma may be detrimental to fetal growth and development in these pregnancies.