Physiologic effects of maternal smoking on breast-feeding infants

Women who smoke and breast-feed pose an unknown threat to their infants' health. In this pilot study, relationships between ingestion of nicotine in breast milk and physiologic effects in the infant were investigated. Infant physiologic effects measured were temperature, pulse, respiration, systolic blood pressure, and oxygen saturation. Five smoking and five nonsmoking mother-infant pairs were studied. Breast milk was analyzed for nicotine using gas chromatography. Breast milk from smoking mothers contained a mean of 33.1 ng/mL of nicotine while the breast milk from nonsmoking mothers contained a mean of less than 6.45 ng/mL of nicotine. Infant physiologic measures were taken before and 20 min after breast-feeding. After breast-feeding, infants of smoking mothers had a significant change in respirations and oxygen saturation while infants of nonsmoking mothers had a significant change in pulse only. Results provide a scientific basis for counseling smoking, breast-feeding mothers.     

The effect of supplemental propionate on insulin responsiveness to glucose and tissue responsiveness to insulin in relation to feeding in sheep

BACKGROUND: Very little is known about the pharmacokinetics of neuroleptic drugs in breast-feeding mothers and their infants or about possible adverse effects in the infants. METHOD: Twelve mothers who breast-fed their infants were prescribed haloperidol, chlorpromazine or trifluoperazine. Two methods, enzyme immunoassay (EIA) and high performance liquid chromatography (HPLC) were used to assay these drugs in samples from mothers, but infants' samples were assayed only by the more sensitive EIA. Repeated clinical and developmental assessments of the breast-fed infants were carried out up to 30 months of age. The control subjects were 18 bottle-fed infants whose mothers were also prescribed neuroleptic or mood-stabilizing drugs. RESULTS: The total concentrations of neuroleptic drugs and their principal metabolites in maternal plasma were correlated with concentrations in fore-milk. Infants were ingesting up to 3% of the maternal daily dose per kg body weight and small amounts of the drugs were detected in infants' plasma and urine. Concentrations of haloperidol in the adult range were found in plasma from 2 of 5 infants assayed by EIA but there was no evidence of any acute or delayed adverse effects. Three other breast-fed infants whose mothers were prescribed both haloperidol and chlorpromazine showed a decline in their developmental scores from the first to the second assessment at 12-18 months. CONCLUSION: More extensive longitudinal studies are needed but, in the meantime, there appears to be grounds for caution if breast-feeding mothers are prescribed doses of single or two neuroleptic drugs at the upper end of their recommended ranges.     

Oncogenic ras induces gastrin gene expression in colon cancer

BACKGROUND: Exposure to environmental tobacco smoke is associated with detrimental effects on pulmonary function in children. The authors investigated the relation between airway complications in children receiving general anesthesia and the passive inhalation of tobacco smoke. METHODS: Six hundred two children scheduled to receive general anesthesia were enrolled in this prospective study. The anesthesiologist and the recovery room nurse, unaware of the smoke exposure history, recorded the occurrence of airway complications. A history of passive smoking was assessed by measuring the urinary concentration of the major nicotine metabolite cotinine and by questionnaire. RESULTS: Airway complications occurred in 42% of the patients with urinary concentrations of cotinine > or =40 ng/ml, in 33% of the patients with concentrations of cotinine between 10.0 and 39.9 ng/ml, and in 24% of the patients with concentrations of cotinine < 10 ng/ml (P = 0.01 for the trend among the three groups). The gender of the child (P = 0.001) and the educational level of the child's mother (P = 0.0008) significantly modified the effect of the concentration of cotinine on the incidence of adverse respiratory events. CONCLUSIONS: There is a strong association between passive inhalation of tobacco smoke and airway complications in children receiving general anesthesia. The relationship is greatest for girls and for those whose mothers have a lower level of education. Passive smoking should be regarded as a risk factor in children undergoing general anesthesia.     

Serum sertraline and N-desmethylsertraline levels in breast-feeding mother-infant pairs

OBJECTIVE: The authors' goal was to study the serum sertraline levels of breast-feeding mothers and their infants. METHOD: They obtained serum levels of sertraline and N-desmethylsertraline in nine mother-infant pairs. RESULTS: Sertraline levels were very low (less than 2 ng/ml) in seven of the nine infants and low (3 ng/ml) in one. N-Desmethylsertraline levels were also low (6 ng/ml or less) in seven of the nine infants. One infant had a high level of N-desmethylsertraline, and one infant had unusual serum sertraline and N-desmethylsertraline values (half of its mother's levels). All infants were thriving. CONCLUSIONS: Most breast-feeding infants whose mothers were taking sertraline had very low serum levels of both sertraline and N-desmethylsertraline, consistent with published reports. The authors discuss in detail the one infant with unusually high levels.     

Concentration of metals, ceruloplasmin, metallothionein and the activity of N-acetyl-beta-D-glucosaminidase and gamma-glutamyltransferase in pregnant women who smoke and in those environmentally exposed to tobacco smoke and in their infants. Part I

Concentrations of metals (Zn, Cu, Se, Cd), metallotionein (MT) and ceruloplasmin (Cp), and the activity of N-acetyl-beta-D-glucosaminidase (NAG) and gamma-glutamyltransferase (gammaGT) in pregnant women who smoke and in passive smokers as well as in their newborns were measured. In smoking women a many-fold increase in cotinine concentrations in maternal and infant urine, amniotic fluid, placenta and milk was found as compared to passive smokers. Smoking lowered serum Se concentration in mothers and infants, increased serum ceruloplasmin in mothers and decreased serum Cu concentration in infants. Serum Zn level in infants was higher than in mothers, and smoking furthered its increase. Statistically significant increase in concentrations of Cd in placenta, amniotic fluid and milk, of Cu in placentae and amniotic fluid and of Zn in placenta and milk was revealed. Higher concentrations of metals were accompanied by an elevated MT level in placenta and amniotic fluid. In smoking women a significant increase in NAG activity in urine, amniotic fluid and milk, increase in gammaGT activity in urine and amniotic fluid and decrease in gammaGT activity in milk and placenta were observed. There was high, positive correlation between MT/NAG and MT/gammaGT in amniotic fluid of passive and active smokers, while similar correlation in milk was indicated only in the group of active smokers. The biochemical parameters analysed proved their usefulness in the evaluation of effects of exposure to cigarette smoke on pregnant woman and her fetus.     

Effects of maternal smoking during pregnancy and a family history of asthma on respiratory function in newborn infants

INTRODUCTION: Infants of mothers who smoke have reduced respiratory function and are more likely to develop wheezing. Little evidence is available on the effect of in-utero cigarette-smoke exposure as opposed to postnatal exposure to environmental tobacco smoke. We used a previously validated non-invasive method to measure the time to peak tidal expiratory flow (tPTEF) as a proportion of expiratory time (tE) in newborn infants soon after birth to examine the effects of a family history of asthma and in-utero cigarette-smoke exposure on the infants' respiratory function. METHODS: We collected respiratory-function data from 500 healthy infants of mothers taking part in the Western Australia Pregnancy Cohort Study. During behaviourally defined quiet sleep, measurements were obtained a median of 58 h (range 26-159) after the infants were born. We used uncalibrated inductance plethysmography. The uncalibrated volume signal was differentiated to flow and used to calculate respiratory rate, total inspiratory time, tE, and tPTEF. Mothers answered questionnaires on demographic, medical, and pregnancy characteristics, including smoking history. Serum cotinine measurements were available to validate self-reported smoking history in a subset of mothers (238). RESULTS: Data suitable for analysis were obtained from 461 infants. In multivariate regression analysis, lower values of tPTEF/tE were independently associated with respiratory rate (beta coefficient per 10 breaths/min 0.018 [SE 0.005], p < 0.01), age (beta coefficient per 10 h -0.008 [0.003], p < 0.01), maternal smoking during pregnancy (> 10 cigarettes daily; beta coefficient -0.049 [0.022], p < 0.05), maternal hypertension during pregnancy (-0.037 [0.015], p < 0.02), and a family history of asthma (-0.028[0.014], p < 0.05). CONCLUSIONS: In-utero smoke exposure, a family history of asthma, and maternal hypertension during pregnancy are associated with reduced respiratory function after birth. We speculate that these factors adversely affect lung development in utero.     

A novel thermostable nitrile hydratase

Adverse effects of maternal smoking have been mostly identified through epidemiologic investigations that have used questionnaires to assess active and passive smoking. However, unvalidated self-reports of cigarette smoking may bias true estimates of relative risk of smoking-related health outcomes. This report is based on two separate investigations. First, within a molecular epidemiologic study of the relationship between environmental exposures (smoking, air pollution, diet) and developmental impairment, we have compared self-reported tobacco smoke exposure during pregnancy to plasma cotinine measurements in mothers. One hundred and fifty-eight patients from obstetrical wards in Cracow and in Limanowa, Poland were included in the parent study. Biochemically-identified smokers were defined as persons with plasma cotinine levels greater than 25 ng/mL. The data showed that exposure classification based on self-reported smoking status compared with cotinine values was of low sensitivity (52%) but of high specificity (98%). We assessed the effect of this exposure classification error on the association between low birth weight (LBW) and smoking in pregnancy using data from a related epidemiologic study of children's health in Cracow involving 1115 subjects. The odds ratio (OR) estimates for smoking and LBW after adjustment for exposure misclassification error were significantly higher than before adjustment (crude OR = 2.9, corrected OR = 5.1). The estimated attributable fraction (AF(pop)) based on the crude OR amounted to 22%; however, after adjustment it reached 50%. The corresponding values for the attributable fraction in the exposed group (AF(exp)) were 66% and 80%. These results illustrate the value of validating questionnaire responses on smoking during pregnancy against reliable biologic markers.     

Objectively measured tobacco exposure during pregnancy: neonatal effects and relation to maternal smoking

OBJECTIVES: To measure quantitatively and objectively the maternal and fetal tobacco exposure during pregnancy and its neonatal effects. DESIGN: Tobacco exposure was assessed from maternal serum samples, obtained during the first half of pregnancy and from umbilical serum samples obtained at delivery, by measuring the concentration of nicotine metabolite, cotinine. Data on the respective pregnancies and neonates were collected from the Finnish Medical Birth Registry. SETTING: Finland. SUBJECTS: One thousand two hundred and thirty-seven pregnancies and newborns, representing all pregnancies resulting in a liveborn infant during one week in one country. MAIN OUTCOME MEASURES: Gestational age, birthweight and crown-heel length of newborns. RESULTS: Cotinine (> 6 micrograms/l) was detected in either maternal or umbilical serum in 300 pregnancies, and these mothers and newborns were classified as exposed. Important differences occurred between measured exposure and reported smoking behaviour. Of the exposed mothers, 38% were nonsmokers and 3.4% of the nonexposed mothers were smokers. Tobacco exposure was associated with shorter gestational age, reduced birthweight and shorter crown-heel length of the newborns. After correction for parity, gender, and gestational age, the exposed newborns were on average 188 g (95% confidence interval (CI) 123-253 g) lighter and 10 mm (95% CI 7-13 mm) shorter than the nonexposed newborns. One micrograms/ml of cotinine in maternal serum resulted in a mean decrease of 1.29 g (95% CI 0.55-2.02 g) in birthweight and in a mean decrease of 0.059 mm (95% CI 0.035-0.083 mm) in birth length. Maternal cotinine concentrations better explained the neonatal findings than the reported smoking habits. CONCLUSIONS: There is a quantitative dose and effect relation between tobacco exposure and a decrease in the gestational age at birth and size of the neonate. The smoking habit reported by mothers themselves is not an accurate measure of fetal tobacco exposure.     

Analysis of nicotine and cotinine in the hair of hospitality workers exposed to environmental tobacco smoke

The purpose of this study was to determine if hair nicotine and cotinine levels reflect relative exposure to environmental tobacco smoke (ETS) in subjects who worked in the hospitality industry, where public smoking was permitted. Hair samples from 26 subjects were analyzed by gas chromatograph/mass spectrometry techniques for nicotine and cotinine. An exposure gradient was shown for nicotine but not cotinine. Among nonsmokers, those working in bars where there are no public smoking restrictions had the highest hair nicotine levels, which were close to levels found in smokers. Nicotine measured in hair is useful as a biological marker for exposure to ETS from multiple sources. Bar workers in particular are exposed to high levels of ETS, which may adversely affect the health of nonsmokers.     

Absence of infection in breast-fed infants born to hepatitis C virus-infected mothers

The role of breast-feeding in perinatal transmission of hepatitis C virus (HCV) was explored in 15 HCV-infected mothers and their infants. The 15 carrier mothers had anti-HCV titers ranging from 1:80 to 1:40,000 and also had HCV-ribonucleic acid with concentrations ranging from 10(4) to 2.5 x 10(8) copies/ml. Both anti-HCV antibody and HCV-ribonucleic acid were present in colostral samples in much lower levels, but none of the 11 breast-fed infants had evidence of HCV infection for up to 1 year of age. Thus breast-feeding seems safe for these infants.     

Human immunodeficiency virus and resistance]

CONTEXT: Racial differences in tobacco-related diseases are not fully explained by cigarette-smoking behavior. Despite smoking fewer cigarettes per day, blacks have higher levels of serum cotinine, the proximate metabolite of nicotine. OBJECTIVE: To compare the rates of metabolism and the daily intake of nicotine in black smokers and white smokers. DESIGN: Participants received simultaneous infusions of deuterium-labeled nicotine and cotinine. Urine was collected for determination of total clearance of nicotine and cotinine, fractional conversion of nicotine to cotinine, and cotinine elimination rate. Using cotinine levels during ad libitum smoking and clearance data, the daily intake of nicotine from smoking was estimated. SETTING: Metabolic ward of a university-affiliated public hospital. PARTICIPANTS: A total of 40 black and 39 white smokers, average consumption of 14 and 14.7 cigarettes per day, respectively, of similar age (mean, 32.5 and 32.3 years, respectively) and body weight (mean, 73.3 and 68.8 kg, respectively). MAIN OUTCOME MEASURES: Clearance (renal and nonrenal), half-life, and volume of distribution of nicotine and cotinine and the calculated daily intake of nicotine. RESULTS: The total and nonrenal clearances of nicotine were not significantly different, respectively, in blacks (17.7 and 17.2 mL x min(-1) x kg(-1)) compared with whites (19.6 and 18.9 mL x min(-1) x kg(-1)) (P=.11 and .20). However, the total and nonrenal clearances of cotinine were significantly lower, respectively, in blacks (0.56 and 0.47 mL x min(-1) x kg(-1)) than in whites (0.68 vs 0.61 mL x min(-1) x kg(-1); P=.009 for each comparison). The nicotine intake per cigarette was 30% greater in blacks compared with whites (1.41 vs 1.09 mg per cigarette, respectively; P=.02). Volume of distribution did not differ for the 2 groups, but cotinine half-life was higher in blacks than in whites (1064 vs 950 minutes, respectively; P = .07). CONCLUSIONS: Higher levels of cotinine per cigarette smoked by blacks compared with whites can be explained by both slower clearance of cotinine and higher intake of nicotine per cigarette in blacks. Greater nicotine and therefore greater tobacco smoke intake per cigarette could, in part, explain some of the ethnic differences in smoking-related disease risks.     

Adverse influence of cigarette smoking on the endothelium

The effect of smoking on the blood vessel intima was examined by comparing indices of endothelial activity in serum from smokers with that from non-smokers. Serum from smokers contained higher levels of von Willebrand factor (p < 0.01), the smoking markers cotinine (p < 0.02) and thiocyanate (p < 0.01), and was more cytotoxic to endothelial cells in vitro (p < 0.02) than serum from non-smokers. The acute effects of smoking two unfiltered medium tar cigarettes was to briefly increase von Willebrand factor (p < 0.001) and cytotoxicity of serum to endothelial cells in vitro (p < 0.005), but lipid peroxides or thiocyanate were not increased by this short exposure to tobacco smoke. Although there were correlations between von Willebrand factor and smokers consumption of cigarettes (r = 0.28, p < 0.02), number of years smoking (r = 0.41, p < 0.001) and cotinine (r = 0.45, p < 0.01), the tissue culture of endothelial cells with physiological levels of thiocyanate or nicotine suggested that these two smoking markers were not cytotoxic. They are therefore unlikely to be directly responsible for increased von Willebrand factor in the serum of smokers. We suggest that smoking exerts a deleterious influence on the endothelium and that the mechanism is complex.     

Joint influence of alcohol, tobacco, and coffee on biological markers of heavy drinking in alcoholics

BACKGROUND: Recent reports suggest that gamma-glutamyl transferase (GGT) decreases with coffee intake. The aim of this study was to examine the joint influence of alcohol, tobacco, cotinine, coffee, and caffeine on biological markers of heavy drinking in an alcoholic population. METHODS: Subjects were 160 alcohol-dependent inpatients. Biological assessments, performed at admission, were plasma levels of GGT, apolipoprotein AI, aspartate aminotransferase, and mean corpuscular volume (MCV), and urine cotinine and caffeine indexes. Years of alcohol abuse and of smoking, alcohol and coffee intake, and smoking rate were estimated in a semistructured interview, and Fagerstr?m Tolerance Questionnaire was completed by inpatients. RESULTS: Coffee intake, but not caffeine, correlated negatively with biological markers of heavy drinking, after controlling for alcohol and tobacco intake. Years of smoking correlated positively to MCV, after controlling for alcohol and coffee intake. CONCLUSIONS: Concerning the effect of coffee, the most likely hypothesis is that noncaffeine coffee fractions have a protective effect on liver cells. Concerning the effect of smoking, one can propose that the increase of MCV with smoking could be a consequence of carbon monoxide inhalation, leading to hypoxemia, or of folate deficiency.     

Sleeping position, orientation, and proximity in bedsharing infants and mothers

The impact of mother-infant bedsharing on infant sleeping position, orientation, and proximity to the mother was assessed in 12 breast-feeding Latino mother-infant pairs. Six routinely bedsharing and six routinely solitary-sleeping pairs slept 3 nights in the sleep laboratory. The first night matched the routine home condition, followed by 1 bedsharing night and 1 solitary-sleeping night in random order. During bedsharing infants were never placed prone, regardless of their routine sleeping condition. On the bedsharing night, mothers and infants spent most of the night oriented toward each other; seven of 12 infants remained oriented toward their mothers the entire night. While sleeping in a face-to-face orientation, most pairs slept most of the time less than 30 cm apart with appreciable amounts of time at less than 20 cm. This orientation and proximity should facilitate sensory exchanges between mother and infant which, we hypothesize, influence the infant's sleep physiology and nocturnal behavior. We conclude that bedsharing minimizes the use of the prone infant sleeping position, probably in part to facilitate breast feeding. By promoting nonprone positions, bedsharing may protect some infants from sudden infant death syndrome (SIDS), since prone sleeping is a known risk factor for SIDS. The large percentage of the night that mothers spent oriented toward their infants suggests that a higher degree of maternal vigilance may also result from bedsharing.     

The smoking addiction of pregnant women and the consequences on their offspring's intellectual development

Many scientists have studied the effects of smoking by pregnant women on intrauterine development. Because nicotine and other toxic substances in cigarette smoke are not stopped by the placental barrier, there is a risk that the development of the child could be hindered. It has been shown, for instance, that babies whose mothers smoked during pregnancy have lower size and weight at birth. Few authors have studied the consequences a mother's pre-natal smoking may have on the intellectual development of her child. We compared two samples of children, aged 4 to 5, and aged 6 to 7 (40 children in total), whose mothers had smoked during pregnancy, with two samples of 40 children of the same ages whose mothers had not smoked. We tested them on the Wechsler scale. The social and cultural levels were equivalent. We found a difference of more than 15 IQ points in favor of the children of nonsmoking mothers. These results permit us to suppose that smoking during pregnancy hinders the intellectual development of the child.     

Prevention of asthma

Infants born of allergic mothers but normal fathers, who had eczema and who were fed cows' milk, had a significantly greater incidence of asthma (P less than 0.001) than infants with a similar history but who were breast-fed. An analysis of all breast-fed infants in the study showed that they were less likely to develop asthma than those who were bottle-fed (P less than 0.06). There was a lower incidence of allergy in infants born of families with allergic mothers and normal fathers, than in families in which both parents were allergic (P less than 0.02). In skin tests of both breast or bottle-fed babies, the two most common allergens eliciting reactions were egg and cat dander.     

Maternal smoking during pregnancy and childhood cancer

The association between maternal smoking during pregnancy and childhood cancer was investigated using prospectively collected data from 54,795 liveborn children in the Collaborative Perinatal Project (1959-1966). Cases of cancer had a histologic diagnosis and/or a compatible clinical course. There were 51 children with cancer, for a cumulative incidence of cancer of 1.1 per 1,000 by 96 months of age. Maternal smoking was determined at each prenatal visit; 52% of mothers reported smoking at one or more visits. By age 8 years, cancer had occurred in 1.4 per 1,000 children whose mothers did not smoke during pregnancy, compared with 0.9 per 1,000 children whose mothers smoked (p = 0.15 by log rank test); the hazard ratio was 0.67 (95% confidence interval (CI) 0.38-1.17). There was no dose-response effect of smoking compared with nonsmokers (hazard ratio for one to 10 cigarettes/day = 0.45, more than 10 cigarettes/day = 0.83). The hazard ratio for leukemia among children whose mothers smoked was 0.82 (95% CI 0.31-2.11); the hazard ratio for cancers other than leukemia was 0.60 (95% CI 0.30-1.20). Adjustment did not change the hazard ratio substantially. Although the relatively small number of cases precluded extensive study of individual types of cancer, the authors conclude that maternal smoking during pregnancy is not associated with an increased risk of childhood cancer in this cohort.     

Distribution of major and minor alkaloids in tobacco, mainstream and sidestream smoke of popular Indian smoking products

Various Indian smoking products--cigarette, bidi, chutta and a brand of US cigarette--were analysed by gas chromatography-flame ionization detection (GC-FID) for the levels of nicotine and minor tobacco alkaloids in tobacco, mainstream smoke (MS) and sidestream smoke (SS) employing modified smoking standards, namely two puffs/min. The analysis clearly demonstrated relatively higher levels of nicotine and minor tobacco alkaloids in tobacco from bidi (37.7 mg/g) and chutta (34.5 mg/g) when compared with Indian and US cigarettes (14-16 mg/g) studied. Relatively lower levels (SS/MS) of nicotine in SS from bidi and chutta compared with Indian/US cigarettes, suggest that the contribution of nicotine in SS from a single bidi/chutta to environmental tobacco smoke (ETS) is very much less than that of a single Indian/US cigarette. Reduced levels of nicotine in SS of bidi/chutta result in relatively higher deliveries of nicotine in MS as reflected by higher MS/SS values. The observed differences are likely to be due to difference in tobacco processing, burning rate/temperature and design of the smoking product.     

Household and community determinants of exposure to involuntary smoking: a study of urinary cotinine in children and adolescents

The study examines the role of several potential predictors of urinary cotinine levels in a cross-sectional sample of 1,072 nonsmoking children and adolescents in Latium, Italy, during 1990-1991. As expected, there was a strong relation between passive exposure to smoking and the amount of maternal and paternal self-reported smoking. The urinary cotinine level increased with a decreasing level of paternal education and with an increasing index of household crowding; self-report of recent exposure to smoking outside the home was a strong predictor of the biologic marker. The analysis was then restricted to 346 subjects whose parents claimed that they were nonsmokers and that there were no smokers at home. In this group, however, 57 children reported some active smoking at home by their parents. Those with parents suspected to be "deceivers" had higher level of urinary cotinine than did those truly not exposed. In addition, urinary cotinine in this group was clearly associated with duration of exposure to smoking outside home. The study indicates that both factors related to family circumstances and exposure outside the household setting are strong determinants of urinary cotinine levels. The finding may be considered a direct confirmation that passive smoking among children should be viewed as a specific community responsibility.     

Cocaine and tobacco use and the risk of spontaneous abortion

BACKGROUND: Cigarette smoking and cocaine use may be risk factors for spontaneous abortion, but data supporting such a link are limited. METHODS: We studied the associations between cocaine and tobacco use and spontaneous abortion among pregnant adolescents and women (age range, 14 to 40 years) who sought care at an inner-city emergency department. A total of 400 adolescents and women had spontaneous abortions either at study entry or during follow-up (which lasted until 22 weeks' gestation), and 570 adolescents and women remained pregnant past 22 weeks' gestation. Cocaine use was measured at base line by self-reports and analysis of urine and hair samples. Cigarette smoking was measured by self-reports and urine analysis. RESULTS: The adolescents and women in both groups were predominantly black and of lower socioeconomic status. Among those who had spontaneous abortions, 28.9 percent used cocaine on the basis of hair analysis and 34.6 percent smoked on the basis of a urine cotinine assay, as compared with 20.5 percent and 21.8 percent, respectively, of the adolescents and women who did not have spontaneous abortions. The presence of cocaine in hair samples was independently associated with an increase in the occurrence of spontaneous abortion (odds ratio, 1.4; 95 percent confidence interval, 1.0 to 2.1) after adjustment for demographic and drug-use variables. However, the use of cocaine as measured by self-reports and by urine analysis was not. The presence of cotinine in urine was also independently associated with an increased risk of spontaneous abortion (odds ratio, 1.8; 95 percent confidence interval, 1.3 to 2.6). Twenty-four percent of the risk of spontaneous abortion could be related to cocaine or tobacco use. CONCLUSIONS: Cocaine and tobacco use were common in our study population and were associated with a significant risk of spontaneous abortion.